Download Proton GE 7.43 using ProtonUp-QT and select it in the game's Compatibility under Properties. Game works flawlessly after that.
Unable to click on the launcher buttons via trackpad, need to use the touchscreen for that
Unable to click on the launcher buttons with the trackpad, need to use external mouse or touchscreen to do so
Proton Version has to be changed to GE-Proton 7.43, also the startmenu has issues recognizing the trackpads, need to use external mouse or the touchscreen to click on icons there, ingame everything works fine.
Just install GE Proton 7.43 through ProtonUp-Qt and change it in the compatibility settings in Steam before your first launch, no issues afterwards on my side
My personal preference is using the left trackpad as the mouse and the right one as a single button (LMB). You'll need to use the cursor (though you could also use the touchscreen, I guess) to change the game's settings, enable gamepad, and navigate PlayOnline and start the game
At first I launched the game with the default Proton version. It seemed to run flawlessly, but I decided to switch to the recommended version (4.11-12 or 4.11-13, the latter of which was the only one available for me) just in case I'd run into any issues using the default version. I had a single crash upon changing zones so far (with the recommended Proton version, though I recall retail being a bit unstable even on Windows), but no other problems.
Considering how much of a pain retail is to set up on Windows, I was expecting it to be worse on the Deck, but it was the exact same experience. I didn't even have to switch to desktop mode. I just recommend being very careful if you're resubbing after a long time away as the process to get your account up and running again is finnicky and COSTS MONEY on top of the monthly fee! The Square Enix website charges you £1 to change your payment method and as I ket getting an error (even after setting it up once, it didn't seem to save the information at all), I had to attempt to set everything up about four times, meaning I had to pay around £4 on top of the £8-9 for the basic sub fee. I've no clue if this money will be refunded, but there's your warning.
Other than all that, actually playing the game on the Deck is such a dream for me. I love this device and although I don't have as much of an attachment to FFXI as many others, I do love this game and I think once you get past the PlayOnline nonsense, it ends up being one of those games that feel like they were made for the Steam Deck. If you're considering it and think the set up process might be worse on Linux, fret not: it's the exact same as on Windows. No more, no less.
Runs great on the Steam Deck
Runs out of the Box for me, only used Custom Layout for Gamepad.
Setting everything up is an absolute nightmare but after everything is set up playing is flawless
LUTRIS_SKIP_INIT=1 flatpak run net.lutris.Lutris lutris:rungameid/1
Added a lot of commands to the trackpads setting them up as D-pad. Such as Ctrl+J, Ctrl+E, Ctrl+I, Ctrl+W, Ctrl+B and used the back grip buttons to pop up Linkshell, Party and Reply chats also making them automatically pop up the keyboard. Because of the low FPS this game is capped at I had to add a hold delay on the control key for all of those macros and n order to make them work 100% of the time.
I found Lutris the best way to play this game because the install script adds dgvoodoo support, however for some reason you have to switch to desktop mode, launch the game via lutris and then to back to game mode and launch it. If you don't launch it first in desktop mode, it just doesn't launch
Small microstutters not very often
I had to set Playonline to boot on full screen or otherwise after a few launches it would no longer run. I have the feeling it has to do with the PoL window position as when I played with an extra monitor connected via USB hub, when moving the window to the 2nd monitor PoL would freeze, then moving it back to the deck screen it would unfreeze.
For the deck set PoL to run on full screen and make sure to enable gamepad support. For FFXI set the resolution to 1280x800 and enable gamepad and xinput. High graphics settings works fine. Also I launch with Ashita for some gear swapping, Ashita is just another burden to set up but once set up it works just fine. Note that the Ashita launcher doesn't work tho so you'd have to configure it through the xml files and launch via injector.exe
FFXI doesn't support windowing without the use of windower
FFXI runs better on Linux with higher degree of compatibility than on a modern Windows OS
I found it difficult to get the game itself running because of the whoops involved with the launcher and the process to get into the game itself is pretty complicated. This shouldn't be held against the Proton since these same problems exist on Windows as well. All the settings did work as intended and I didn't find any faults that are worth mentioning. However I absolutely have to add that like with e.g. Delta Force 2... the FFXI runs in-fact better with Proton than in actual real Windows environment. There are some bugs and glitches in FFXI on Windows which do not make an appearance on Linux when run through Proton. For example, by using FFXI PS2 release as a reference point, some of the weather patterns such as rain and mist look and work as intended on Linux where as on Windows they sometimes are missing or visually broken. Also I don't recommend attempting to break the intended FFXI out-of-box experience. When modded with suitable utilities to break free of the 30 FPS limit this game has it can in-fact run so much faster than on Windows that it becomes a problem in and itself.
Everything works out of the box without any issues