

On launch the Ubisoft Connect launcher opens, after signing in you can run the game perfectly

Ubisoft Connect gives an error message by default. Forcing Proton Experimental fixes this and Ubisoft Connect and the game run fine.
Forcing Proton experimental is the only tinkering required,then it runs fine.

Cannot currently be played on SteamDeck regardless of proton version selected due to Ubisoft Connect issue.
Launching the game via steam launches Ubisoft Connect. When you attempt to login in to ubisoft connect and error is shown which reads: "Connection lost A Ubisoft service is currently unavailable. Please try again later."
Addtionally I tried instaling and launching ubisoft connect via desktop mode as shown here and ran into an identical issue: https://youtu.be/CAfiShbbkzs
screenshot: https://steamcommunity.com/sharedfiles/filedetails/?id=3002972965
Valve has fixed Ubisoft Connect compatibility if you use Proton 7.0-6 or Proton Experimental.
Disabled Back Grip Buttons
Ubisoft Connect is broken on Steam Deck now resulting in an error when attempting to play the game.
Hopefully they fix it.
Game plays singleplayer and local multiplayer flawlessly once everything is setup, you just have to make sure GamePad is enabled before bootup (controller icon to the right of the play button). The other issue you might encounter is with the secondary launcher. I highly suggest you have your Ubisoft and Steam accounts linked before booting the game on SteamDeck. If you have access to a PC, link the accounts there and make sure it boots properly. Then you shouldn't get any major problems when booting up Ubisoft games on the Deck. I did have to reboot once as it just hung on the in-game client patcher but has worked fine since.
changed right trackpad click to lmb
ocasionally missing audio at the start of boss battles
Ubisoft Connect required to play (offline and online)
Audio queues didn't play, this was very rare though.
You can't play online because of Denuvo anti-cheat (and possible Ubisoft Connect), you will get kicked out and given an error code.
I tried to play with friends on the Steam Deck but always got the error code. The moment I played it on Windows I joined their game no problem.
Changed trackpad click to LMB for easier launcher usage
The launcher won't auto-open keyboard. The launcher won't let you start the game when you're offline, even if you played and activated the game previously. Even if you go online when the launcher prompts you to you won't be able to start the game, unless you restart it fully trough steam.
If you get into the game, and then sleep -> awake the Steam Deck the game will continue to work properly.
The launcher starts Ubisoft overlay in background. If you open it in any way (for example by trying to check in-game Achievements option) it starts draining battery with 20W, and if you have TDP limit it will be basically unusable(you can otherwise set the limit to 3W and keep 60FPS). It is a problem, because you can get into overlay by accident just by using in-game menu, with no warning that you'll be redirected to the overlay.
Trying to find online match returns RYAN-3033 error. When trying to host a game there's "Invite a friend button" but it opens Ubisoft client and it says I can't send an invite because I'm not in a multiplayer game session, so I don't think it works.
Works perfectly fine if you're playing offline, assuming you were online when launching the game. I tried local co-op with 4 controllers and it all worked fine, but I had to set gamepad layout for all 4 controllers (they all default to KB+M). Ubisoft launcher is a pain, the game doesn't integrate well with Steam features, and if you're looking for an online experience I don't think it works. Although I couldn't get it to work even on Windows.
Online doesn't connect. UPlay overlay stuck in top right corner.
To get rid of the UPlay overlay welcome message that stays stuck in the top right. Press Shift + F2 to open the overlay, and under the notification settings turn off all of them. Close the overlay, if it gets frozen open, just close/crash the game and start it again.

Disabled Back Grip Buttons
This game uses Ubisoft Connect. I had already installed South Park the Fractured But Whole on the Steam Deck so it launched without any issues, but if you have issues launching it, you might wanna follow instructions listed on that game's page.
Ubisoft Connect no causa ningún tipo de problemas, y lo único que se puede configurar son el sonido y el audio, más no podemos cambiar la resolución, sin embargo funciona perfectamente a nivel de rendimiento y estético.
Works fine in both online and offline play. Ubisoft connect navigation still sucks though and the game would be a lot better without that bloatware
I had to run the install twice in order to get the game to launch. Also, disable Steam Input if you're playing with a controller.
Due to the game using 8-channel surround with XAudio, the audio ends up being rather quiet. This is an issue with the port itself.
I had to disable Steam Input in order for my Xbox controller to work.
I couldn't connect to my friend for online play, but this is also an issue with the port.
Cannot proceed into the game or any menus