https://bugs.winehq.org/show_bug.cgi?id=51449
--- Comment #3 from Yao Mitachi yaomtc@protonmail.com --- Yes, that custom launcher works great, and also the Lutris x86_64 installer worked for me, under "unpublished installers" here: https://lutris.net/games/final-fantasy-xiv-endwalker-benchmark/
The concern is whether the old launcher (which works in Wine, and users can currently enable by changing a value in a config file) will work. It's possible they may drop the old launcher. If so, users will have to use XIVLauncher unless there's a dotnet48 integration into Wine or Proton in the next few months.
https://github.com/goatcorp/FFXIVQuickLauncher/