
Lower FPS limit to 40 FPS.
I set the frame limit in-game to unlimited, but had the Steam Deck limit to 40 FPS on all medium settings (AA was set to high) with resolution scaling at 85%. The game was incredibly stable with these tweaks, and given what the game is, 40 FPS is a perfect sweet spot.

Did not work with dx12 for me, works perfectly in dx11 mode though
I used PS4 controller, worked perfectly, but I had to turn off steam input because it is marked as uncompatible with my controller for some reason. Works perfectly though

gamescope -w 2560 -h 1440 -W 3840 -H 2160 -F fsr -f -e -- %command%
With Gamescope I use AMD FidelityFX Super Resolution 1.0 to stretch the resolution from 2K to 4K. I set everything but shadow quality to the maximum. I need to downgrade shadow quality to "Very high" for smooth operation. As of this writing, I also need to disable Steam Input due to a know bug in Gamescope.
- inconsistant framerate until restart after leaving and entering the window again
Ran great, no issues

MANGOHUD=1 gamemoderun %command%
RADV_PERFTEST=gpl,nggc,sam

Performs very well with the dx11 renderer, sans brief frametime blips during scene changes. Performance is overal very consistent.
gamemoderun %command%
I didn't have any issues with the main games audio, but with the Wavelengths DLC the first song played during the intro cinematic for each day was very load and blown out compared to any other time music is played in the radio station / store. It was loud enough to be painful, I always had to quickly turn down my headphone amp each time it happened, then raise it back to normal afterwards. Initially I thought Steph was absolutly blasting some noise rock, but on one of the days the audio had subtitles for Steph's internal monologe that was completly inaudable over the song, so I don't think it's intentional. Any song played after the begning of a new day didn't have this problem.
There's a very large perfornace gap between the very high and cinematic presets. Very high is nearly double the perforance for very little loss in fidelity. Unless you have a lot of gpu headroom I'd stick with very high. I played at native 1440p very high and my framerate was typically in the ballpark of 80-110 fps.

Played on cinematic settings, runs just fine
Sometimes I get FPS drops when entering new area. I got similar problems with the Xbox version of the game.

Install and go
No problems at all. My fans started going until I toggled VSync on, after which they immediately went quiet but that was optional. It worked right away and looked great.
Works perfectly fine

Working without issues
Only used the DX12 version

Introduction
This is based on my last report and joroehl's report. There are two options here that you can use: recommended or visuals. (rec) is for saving battery and stable 50 FPS with slightly weak visuals, while (vis) will provide better visuals, while increasing battery usage and erratic FPS between 40-60 (rarely ~30).
Deck Battery Performance Settings
- Frame Limit: 50 Hz (rec) or 60 hz (vis)
- GPU Clock Frequency: 1000 (rec) or off (vis)
- All other settings are turned off. No need for FSR anymore as indicated in my last report.
Steam Launch Options
- DirectX 12
- Note: If you run into issues with it, revert back to pre-selected launch option (which uses D3D11).
In-Game Settings (Video Settings)
- Display Mode: Fullscreen
- Maxmium Frame Rate: 60 FPS
- Vertical Synchironization: Yes
- Resolution Scaling: Yes
- Scaling Percent: 85%
- Anti-Aliasing: Very High
- Shadow Quality: Low [rec] or Medium [vis]
- All other settings: Medium [rec] or High [vis]
Floating text in the distance could be small, but not a huge problem. Approach closer to enlargen text.
This is honestly a surprise for me, considering how heavy of a game this is. The game now runs even better, but will still run considerably slow on Very High and above. D3D12 mode also can be now used without any concerns. (in the tinker steps, I said "rarely 30 FPS", but I actually meant "uncommonly* (facepalm))

I played DirectX 12 version and it runs very well with VKD3D. Not tried DirectX 11 version.

More specifically, i hex-edited the exe to run the game at 16:10, not required but is a bit nicer on the steam deck. https://steamcommunity.com/sharedfiles/filedetails/?id=2597469364 < Follow this guide if you wish to do the same as me, and use "CD CC CC 3F" to replace. If you want to do all this directly on the deck, I believed i used the hex editor ImHex
I used the settings from user joroehl and it runs fine.
In the settings, the text is hard to read.
Insanely low camera sensitivity with mouse, but otherwise perfect out of the box.
Camera sensitivity is insanely low with mouse, but fine with controller.

Capped @ 40Hz and 40FPS
Text in the distance was often hard to discern. Not a problem.
It's not going to look the best, but it's pretty damn good.
Works perfectly out of the box
FPS cap: 30
Finished the whole game on Steam Deck. With the default settings and FPS capped at 30, the games runs well. Experienced one crash during the 15h gameplay. Occasional drops to ~20 FPS, not frequent though.

Default settings are fine. My personal sweet-spot to balance visual-fidelity and battery-life is below.
Changes in the in-game graphics menus:
- activated 30 fps cap
- set resolution scaler to 85%
- increased anti-aliasing to "very high"
- reduced shadow quality to "low"
- increased texture quality to "high"
- everything else set to "medium"
This gives me a good looking game with ~4h of battery life.
I used the pre-selected D3D11 version.
Runs out of the box
Played with all settings as Very High except Shadows set to High. Used Proton 7.0-4.
Run the game in non-DirectX 12 mode. The Dx12 mode doesn't work well. Then, follow the instructions below for better stability and performance. The game can run at 60 fps at lower graphics settings, however, although GPU clock will have to be turned off.
Deck Performance Settings
- Set FPS limit to 30
- Set GPU clock to 1000
- Set scaling to FSR (1x-5x is up to your preference)
In Game Settings
- Set framelimiter to 30
- Set graphics to High
- In Advanced Video:
- Set resolution scaling to 100%
- Make sure everything else is on High (not Very High or Cinematic)
- Turn VSync on
- Set window mode to any options that is not Borderless
Dx12 mode may cause crashes. Also, any graphics settings higher than 'High' may cause crashes.
Works almost perfectly on Proton 7.0-3 but there was infrequent stuttering. After switching to GE stuttering disappeared.
Numerous crashes in between checkpoints. Sometimes I have to hard reset the deck
mangohud %command%
Slowdowns can be annoying, but the game saves frequently enough to just exit out and start up again
Saves randomly deleted themselves when playing DLC and I needed to replay the entire game over again. May actually be a problem with the game itself because Windows players also reported this issue
Game randomly slowed to unplayable framerate, needed restart to fix. When played on experimental proton, the game would crash instead of slow down
Very rare on 6.3-8, fairly frequent on newer protons.
Made it through Chapter 1 on experimental proton without issues, but then it was crashing far too often to play. Needs 6.3-8
Completed game with Proton, had to lower some settings for stability
The game appeared to run first at solid 60fps maxed "Cinematic" settings. But after a while performance tanks and game crashes. So perhaps there is a leak/game eats up all the vram. I lowered some of the settings to very high instead, and set to lower resolution scaling for a stable experience.
Played quite well out of the box, especially for the gold rating it currently has on protondb
I played the first few chapters without any tinkering but crashed twice in probably 8 or 9 hours of play. Which wouldn't be a lot but auto saving is weird so there's a lot of time you have to replay when it crashes.
I switched to Proton-6.21-GE-2 and didn't crash again through the rest of the game.
Ran great, no complaints
Able to install and play with no tinkering required!
I installed the gaming knowing that it was not "officially" supported on Linux but had no issues at all running the game. Everything worked well and fps was always above 60 for my setup. I have happily played the game through almost twice now.
Con ProtonGE sin hacer ningun cambio más, me ha funcionado como nativo durante las 10 horas que dura el juego, si que es un juego que como los anteriores pide bastante gráfica, pero jugado a los gŕaficos mas altos, me ha funcionado sin errores a 60-80 FPS durante todo el juego. Lo he jugado dos veces , sin notar ralentizamiento, ni errores en cinemáticas, ni en el audio.

Finished the whole campaign in Proton.
Only happens occassionallly.
Reducing the ingame shadow settings from "Very High" to "High" mitigates the performance impact.
I encountered one persisting slowdown to ~20fps during my playthrough. After restarting the game the performance was back in track. This may or may not be related to proton.
I used an Xbox controller and the pre-selected Direct3D 11 version.

Default Proton version didn't work. Need to switch back to older version.
Runs perfectly fine and feels like a native game, even with Debian stable packages for kernel and drivers
Minor texture issues makes texture loading slightly slow, but not a big problem
Game was inconsistent on actually launching to the main menu, typically only launching to the game on the first or second try on a full power cycle (shutdown-> press the power button-> boot the game first). Any further launches crashed more often than not, I never got dx12 to run no matter what I did.
When it did (eventually!) launch on the valve tested version of proton (7.0-1), performance was OK in the intro sequence but preseted to very high (30-35fps), low preset with very high textures looked almost as good with higher framerate (45-55fps).
While the performance on a steam deck is passable, I would say to steer clear of this title (specifically on deck) for now.