The steam version is from steam, downloaded from steam and installed via steam. I have tried running it with multiple versions of Proton and Proton-GE to varying degrees of success. It either runs at a single digit frame rate, crashes on start up, or if it manage to get it running okay, it also cannot save.
The version I have installed currently is the fitgirl repack. I downloaded before we started troubleshooting, I had downloaded and installed it on a previous install of mint (I had to wipe that and install again due to me encrypting the home folder and that causing issues. Since then I redownloaded the sims4 FG repack. I installed it for the first time on this install of mint yesterday. Having the same issue with saving as I had on the last install of mint. That time however I used a guide from reddit that was very convoluted compared to how I installed it yesterday.
The current install of TS4 is in /home/user_name/Games/the-sims-4-lutris/drive_c/Program Files/The Sims 4/Game/Bin/TS4_x64.exe
I do not see a way to set the save folder. This was installed via Lutris, and I used this install location because the default when installing was Z:\Games\The Sims 4, but doing so fails. Which is why I have it in c:.
I am wondering if I create the directory first if that will work.
Edit: read your post more carefully and see you gave me your path for install. I used that same path (roughly) still it is using c:\users\user_name\
Installation takes like 2+ hours, so it is working currently.
Was it nightmare?