Works perfectly on Linux Mint 21.3 using Proton 9.0-1.

Closes after launch

Nothing of note, really, though I haven't given this a try with default Proton, as I don't own the game on Steam.

No
Virtual keyboard doesn't work
You can't proceed without keyboard input.
Installed using Heroic Launcher with default settings. I'm unable to input my coach name and surname as virtual keyboard doesn't work.

pixelated if using unconventional resolutions
On latest patch, it would crash whenever I kick off a game. I can start the game - and even play it - just fine, as long as I don't touch the match engine. As soon as the kick off started, it would CTD.
I tried a ton of fixes, windowed mode, etc. nothing works. And seeing how they dropped support right before this patch made me think this is some planned obsolescence trick from SI to force players to upgrade to FM22-23. However, in my desperation I tried old versions of Proton and 6.3-8 fixed everything.
600+ hours and seems to work just fine
Runs flawlessly

Everything works great. The only difference to Windows is that the game tends to run hotter on Windows than on Linux.
For some reason the shortcut had the FM19 icon rather than FM21.
Everything works perfectly.
very rare (about 5) crashes after 250 hours of playing

Experimental Proton
Using an nvidia gpu. With compositor on, manjaro kde, especially opengl, game was unplayable. 10fps and barely able to move the mouse. First changing the compositor to xrender helped a bit, disabling it fixed all issues. alt-shift-f12
Work fine with Proton!
Some Update may broke the game (won't start) but Proton Exerimental fixed it for me

Do not start anymore
It worked, but now it does not work anymore
Doesn't work with flatpak installation of Steam

not running under various proton versions under Linux/Steam
game not running under steam on linux w proton. Tried different versions. After clicking play, shortly "starting" is displayed, but nothing happens. Shortly after that, button returns to "play".

No longer runs
Unfortunately some kind of update must have left it unable to run, natively or using Proton. No clue what is preventing it from running, it was working perfectly a few weeks ago. If I were still invested in my Gloucester City save I would be furious

Doesnt start
Just flickers then play button shows again. Tried different Proton versions
Runs perfectly
With with no significant issues
Crashed when restarting the pc from hibernation
If using Steam installed through Flatpak, the game doesn't work (on Fedora), use dnf (or other package manager) to install Steam. Not sure why this is the case but I tried 3 or 4 different Proton versions on the Flatpak Steam but all failed to launched. Switched to the Steam installed with dnf and it worked flawlessly.
Just launch the game with steam and you can be Tuchel !
I must ajust the settings (medium) for 3D match but i play in 4k.
The cloud save works fine.

Doesn't run at any time
Tried every single tweak on github page, and zero results. This game can't be considered gold when I can't even run it. Trash on Proton, period.
İntel Graphics Driver is okey but when ı activate nvidia drivers just blank screen.

Can't go through blank screen
The game open with a blank screen. Tried different proton versions, also GloriousEggRoll versions with no success.
It works!
Everything works fine. Proton 5.13-6
Game runs out of the box with no major bugs
It's ok for me but online ko
Online ko
The games stuck at blank screen after i hit the play button

Works out of the box with Proton Experimental
For a mostly 2D game the FPS sometimes jumped all over the place from tops of 140 to lows of 30
Worked straight out the box, just as if it was native.

Shows blank screen and became not responding when I press Alt+F4 to close the game
I've try it with Proton 5.13-5 and Proton Experimental but didn't works

Says running, but never launches anything. I have found a error in steam error log related to the wine_server crashing due to memory fault.
Starting the game, the following msgs are reported to the /home/user_name/.local/share/Steam/error.log:
GameAction [AppID 1100600, ActionID 1] : LaunchApp changed task to ProcessingInstallScript with "" _v2-entry-point[43634]: STEAM_COMPAT_APP_ID=1100600 _v2-entry-point[43634]: STEAM_COMPAT_SESSION_ID=9319bb472bff312b _v2-entry-point[43634]: XDG_RUNTIME_DIR=/run/user/1000 _v2-entry-point[43635]: STEAM_COMPAT_APP_ID=1100600 _v2-entry-point[43635]: STEAM_COMPAT_SESSION_ID=9319bb472bff312b _v2-entry-point[43635]: XDG_RUNTIME_DIR=/run/user/1000 esync: up and running. wine: RLIMIT_NICE is <= 20, unable to use setpriority safely wine: Using RTKit to control niceness in the [-15,15] range _v2-entry-point[43983]: STEAM_COMPAT_APP_ID=1100600 _v2-entry-point[43983]: STEAM_COMPAT_SESSION_ID=9319bb472bff312b _v2-entry-point[43983]: XDG_RUNTIME_DIR=/run/user/1000 _v2-entry-point[43999]: STEAM_COMPAT_APP_ID=1100600 _v2-entry-point[43999]: STEAM_COMPAT_SESSION_ID=9319bb472bff312b _v2-entry-point[43999]: XDG_RUNTIME_DIR=/run/user/1000 *** stack smashing detected ***: terminated wine: Unhandled page fault on read access to FFFFFFFFFFFFFFFF at address 00007F46663F7EBD (thread 00b4), starting debugger...
Trying to run it a second time: wine: RLIMIT_NICE is <= 20, unable to use setpriority safely wine: Using RTKit to control niceness in the [-15,15] range ERROR: ld.so: object '/home/user_name/.local/share/Steam/ubuntu12_32/gameoverlayrenderer.so' from LD_PRELOAD cannot be preloaded (wrong ELF class: ELFCLASS32): ignored.
Adding process 49417 for game ID 1263850 *** stack smashing detected ***: terminated wine: Unhandled page fault on read access to FFFFFFFFFFFFFFFF at address 00007F9E6239AEBD (thread 00ac), starting debugger... (END)
I'm a software programmer and I work on Linux a lot. If you want me to help debug this, please let me know.

Stays at "Preparing to launch game". Than screen flickers shortly and than again says "Play"
Proton 5.13-4

Playable despite missing audio
No audio whatsoever
Manager appearance editor appears glitchy. Changing one of the settings (e.g. hairstyle) fixes this
In match engine, sometimes some players will appear as artifacts instead of proper models
The new proton update fixed the problems. Working great so far.

Still not fixed
The same problem as before. A black screen coems up and exits immediately
It's working now, all the way from install to game play. What ever update was made in 5.13-3 has done the job.

Recent "hotfixes" seem to have broken it, even when using latest version of GE.
Unfortunately I've had no luck in getting this to run, even with the latest versions of GE. From my understanding, the most recent hotfixes (26/11/2020) have broken it. Waiting for an update.
Proton-5.21-GE-1

Initially booted through splash screens, now crashes on boot
Using proton 5.13-2. Before the hotfix was released it would boot through the opening splash screens but crash prior to loading the main menu.
Since the hotfix was released, it crashes less than a second after boot.