Proton Prefix Created in Wrong Library Folder in Steam Deck Desktop Mode

[sonic2kk]

Your system information

• Steam client version (build number or date): Nov 19 2022 at 06:48:17
• Distribution (e.g. Ubuntu): SteamOS 3.3.2 Beta
• Opted into Steam client beta?: Yes
• Have you checked for system updates?: Yes

Please describe your issue in as much detail as possible:

Generally, the Proton prefix for games on the SD card are set up appropriately. When installing / moving a game on the Steam Deck to the microSD card in Game Mode, the prefix is created fine. Equally, running a game with an existing created prefix works as expected in Desktop Mode.

When you delete a game's prefix and attempt to recreate it by launching the game from Desktop Mode, the prefix will always be created in the ~/.local/share/Steam/steamapps library folder instead of the one on the microSD card. This causes games to crash as well unless the prefix is moved / symlinked to the microSD card library folder.

If the prefix is deleted, and a launch is attempted from Game Mode, the game will indefinitely hang on the loading screen. Going back to Desktop Mode after this reveals that the prefix is still created in the Steam root library folder instead of the microSD card library folder.

This does not happen on desktop Arch Linux on the Steam Client Beta. On my desktop PC, prefixes are always created in the same library folder as the game.

Steps for reproducing this issue:

1. Install a game on the microSD card from Game Mode
2. From Desktop Mode, delete the Proton prefix
3. Re-run the game from Desktop Mode
4. The Proton prefix will be created at the ~/.local/share/Steam/steamapps/compatdata location, instead of on the microSD card library folder
5. The game will crash unless the prefix is moved / symlinked to the library folder on the microSD card

[sonic2kk]

This is still an issue as of the latest SteamOS Preview. Game prefixes are seemingly always created on the Steam root libraryfolder. Maybe this is dependent on which library folder is selected as the default.

Outside of SteamOS, Steam will create the prefix in the same libraryfolder as the game.