The game is not running directly from Steam. I was able to install Ubisoft Connect and then install the game from that launcher. Guide:

1. On Steam Deck, go to Desktop mode and in your browser navigate to Ubisoft Connect Download page
2. Download Ubisoft Connect, add the exe as a non steam game. Change compatibility to Proton latest version
3. Launch the Ubisoft Connect exe. Install Ubisoft connect, log in.
4. Install the game/this works for other Ubisoft games in your library**Except for EasyAntiCheatgames/
5. While still in Desktop mode, navigate to the Ubisoft Connect exe in Steam and in properties change the launching path to the now installed Ubisoft Connect Launcher/You can find the location in a newly created :C folder in /home/deck/.steam/root/steamapps/compatdata/33320/pfx/drive_c/Program Files (x86)/Ubisoft/
6. After your game has finished downloading, close Ubisoft Connect.
7. Launch Ubisoft Connect from your Steam Library again while in Desktop mode/If you skip this part you might have issues in gaming mode where Gamescope can't decide between showing you the game or ubisoft connect and keeps flashing/
8. Navigate back to gaming mode and launch the Ubisoft Connect exe
9. This will now launch Ubisoft Connect and from there you can select your downloaded game and click play.