Out of the box the game crashes in random intervalls (10min to 6h). First audio cuts off, but you can still save if you are lucky enough to be out of combat/cutscene. Some time after audio cutoff, it crashes completely. This is fixable! Based on a post by u/jimbobvii in r/Falcom:

• Open a web browser and download the XAudio 2.9 redistributable from https://www.nuget.org/packages/Microsoft.XAudio2.Redist/ (Click Download package on the right side of the page).
• Open the downloaded package with Ark or an archive manager of your choice, and extract /build/native/release/bin/x64/xaudio2_9redist.dll
• Copy the redist DLL into the /bin/Win64 subfolder of the game's install directory and rename it to xaudio2_9.dll
• Install Proton tkg (maybe Proton GE works too), I recommend using protonup-qt for easily installing custom proton versions. I used Proton-tkg 7.6.r12
• Restart Steam (or on deck: Exit Desktop mode)
• Right-click on the game in your Steam Library and choose Properties. Under Launch Options, paste WINEDLLOVERRIDES="xaudio2_9=n" %command%, forcing the game to load the downloaded DLL.
• Under Compatibility, check "Force use of...", select Proton-tkg

Didn't encounter any more crashes after doing so. You can also install an unofficial English patch too, should be easy to find on google (I'd say 95% of text are translated). Lets hope we don't have to wait too long for Nisa to make a proper PC port for the west...