I want to replace a save file for a game. I disable steam cloud, use protontricks to find the prefix for the game, find the savefile I want to replace, delete it, put the new one one in its place, and run the game.
Everytime, Steam somehow creates the old existing savefiles out of thin air. When I close the game, the old game saves are back in the folder. Even if I delete the entire save folder, steam somehow recreates the files.
It's as if the launch process for Steam games on linux somehow replicates a cached folder for saves on startup.
For reference, most recent example: the game is The Binding of Isaac: Rebirth. The proton prefix contains the saved games in .../Steam/steamapps/compatdata/250900/pfx/drive_c/users/steamuser/Documents/My Games/Binding of Isaac Repentance/ as 20251228.rep_persistentgamedata3.dat
I delete the entire folder, put in a savefile I downloaded named "20251228.rep_persistentgamedata3.dat" or "persistentgamedata3.dat" (tried both). After game startup, the game contains my old cloud synced saves (with steam cloud disabled!!) and when I refresh the folder, it contains the new backup files for said saves ("20251228.rep_persistentgamedata3.dat").
This is not a BoI-specific issue either. i had the same problem with Absolum and similar problems with Lies of P (altough I managed to get it to work there, I don't know why).
I am now running into this for the second time and there must be something I am fundamentally misunderstanding, but i do not find anything related on the internet. It is as if no one ever had that problem before.