gamemoderun mangohud %command%
When I first installed the game, it wouldn’t launch through Proton, but reinstalling it resolved the issue. Mods work flawlessly via r2modman, and overall performance actually feels better than on Windows. Also, selecting Vulkan in the launch settings can give a slight FPS boost. https://imgur.com/a/NAc0I67
At least 40 fps lower than on Windows

LD_PRELOAD="" %command%
There is currently a bug that degrades game performance significantly if you don't use the aforementioned launch arguements. https://github.com/ValveSoftware/steam-for-linux/issues/11446
Be sure to use those optional arguements in the Properties menu of every game in Steam that isn't linux-native.

Copied the game files from my old Windows to Linux..
Works out of the box, the saves are there, online works, the performance is even slightly faster.

Took some time to load when teleporting, resulting in a few seconds freeze (ONE TIME). otherwise it's smooth sailing. (tested for 1 hour)
I was lucky to run the native client without any real problem. Trying the Windows client with Proton (both Valve and GE) failed, tho.

Modding however is a complete pain in the ass. r2modman doesn't work correctly, I had to resort to directly injecting the mods and using r2mm as a downloader / browser then copying them to the game directory. Otherwise in terms of vanilla gameplay, absolutely flawless, well deserving of Platinum.
The game, for some reason, makes calls to the Steam overlay. If you disable the overlay, these calls stack up and eventually cause significant stuttering after 30'ish minutes of play. Enabling the overlay will completely fix the issue.
As with most Linux native ports (sadly), it isn't built as well as its Windows counterpart and can have a variety of bugs. If you face any issues, just switch to proton as it runs flawlessly.

Works with native support and with proton
Native failed to launch, but running with Proton works perfectly.

Works Great on Proton!
When playing the Native version the mouse cursor would be off by a few pixels when in full screen. I would have to click slightly above menu options for it to register the click. Switching to Proton fixed that issue.

Works out of the box with Proton 9.0-4
Native crashes when resizing the window, but Proton works perfectly.

Switched from Native to Proton Version
At first I tried the Linux native version. After the game crashed twice in the main menu, I decided to try it with Proton which I had no issues with.

Using mods loaded via r2modman.
- After breaking the base off of a stone pillar in the plains biome, my fps drops to 10-15 and does not recover until the game is closed and reopened.
- At seemingly random intervals the game will drop to 1-25 fps for a varied period of time. I cannot deduce a cause for this. These issues occur independent of any graphical settings. I suspect this may be the fault of Unity, as another game made in Unity (Battlebit Remastered) experiences a similar issue (stable capped 70fps normally, drops to under 10fps about every 20 minutes for a period of 1-2 minutes).
The issues I have noticed occur almost exclusively on dedicated servers. I only experienced issues a few times in singleplayer, and they were much less severe. If you do play multiplayer, I suggest hosting it yourself either dedicated or through the ingame hosting menu.
env --unset=SDL_VIDEODRIVER %command%
Hyprland xwayland issue but SDL_VIDEODRIVER fixed this problem

Running Native without mods works out of the box, performance is better than windows or via proton.
./start_game_bepinex.sh %command%
Running mods using BepInEx required changing compatability to "Legacy runtime 1.0"

Running mods; had to use proton for r2modman to work
Since I'm running mods, that was a bit of a hassle to setup. Basically I had no luck running mods until I ran valhiem with proton and left the steam launch options blank.

The game works perfectly fine native
The proton version works, but has severe memory leak issues in my experience, Copper mining also makes the frames drop when "exploding" a node Native modding can be a bit of a pain manually but is completely possible
systemd-inhibit game-performance %command%

The native version runs better than the Windows version through proton
I found that while running the Windows version through Proton and GE-Proton actions that cause a large amount of drops to spawn would cause the framerate to crash to 2-3 fps and it wouldn't improve until restarting the game.
Actions that caused the framerate drop
- destroying a silver vein by fully excavating it then hitting it
- colosseum destruction in fader boss fight
Both these actions caused no issues when running the native version
Runs great using default stable Proton

The Native version would drop down to 20 fps after about 5 minutes of play. Switching to proton ran the game smoothly with no issues

Game runs great with Proton experimental. Not a single issue I've encountered after ~10 hours of gameplay.

Works perfectly in multiplayer
Played with friends for the first time on linux and it worked right out the box. No configuration needed.

Na versão nativa o jogo fecha aletóriamente. Proton Experimental + Vulkan resolve.

I was able to get to the menu and create a character. However it crashed when starting a new world then crashes on startup after that.
After some troubleshooting I found that installing the "amdvlk" package let Valheim start without issue. I was working solely on "vulkan-radeon" when it wasn't working. This works on Arch Linux, so I can't speak for any other distro. You can also use the launch option "Play Valheim using OpenGL" and that works without issue too.

Game freezes until crash at random points while playing
Native freezes on launch

Initially the game would crash during world generation/loading when running natively. However, switching to "Play Valheim using OpenGL" fixed that issue. The caviat being performance was terrible in comparison.
I found that "Play Valheim using Vulkan" when launching through Proton is the most performant, by far.
Native Support. Runs better than windows
Amazing native build. No issues and runs perfectly

Game works and runs perfectly, but playfab if needed does need additional setup

Gamescope settings: Frame limit 45fps/90hz
Game settings: Performance graphic mode
By default, it uses the wrong audio output. Switching in Ubuntu settings fixes the issue.

No audio if using native
I had to use GE-Proton9-13 to have audio and be able to connect any server

While the game runs natively on linux, there's a weird bug where the game doesn't center the cursor to the middle of the screen when opening the inventory menu.
Force the game to run with proton and it will behave exactly as it should.
gamemoderun mangohud %command%

läuft ootb sowohl nativ als unter proton 9.xx

Very Fun Game
I like when games are native :D

Works just fine. No audio problems
I have no isuses on Endevor OS.
On linux Mint I did have audio problems that were fixed by switching audio devices to something else then back to the one I was using. That is one of the reasons I swapped Distros, Mint does not handle audio well.

Game uses audio cues, so no audio impacts gameplay. Music significant part of establishing atmosphere.
No audio. Other reporters suggesting some launch options, or switching audio device after launch. This did not fix the issue.
Works if you're fine with zero audio. Other reporters have been able to fix the issue, not me.