Unable to install any version of dotnet on a 64 bit prefix - GTA4 complete edition - Steamdeck

[Ky0sann]

Describe the bug
I installed GTA4 complete edition via steam on my steamdeck and I'm trying to get .net mods to work. So I install GTA4 Script hook dotnet and it asks me to install the .net component, as usual I go to protontricks and do “install a window dll or component” and I select dotnet40 then I install it but no matter what I do or what version I try to install, the installation fails every time.

To Reproduce
Steps to reproduce the behavior:
1 - Add the ScriptHook.dll and ScriptHookDotnet.asi files to the GTA4 file
2 - Go to protontricks, select the default GTA4 prefix
3 - Go to Windows DLL or component
4 - Select dotnet40 and launch installation
5 - Wait a while and the installation will fail

Expected behavior
dotnet40 should install successfully and in “uninstaller” I should see dotnet40 in the list of applications installed in my prefix.

System (please complete the following information):

• Distro: Steam Deck with Steam OS current version
• Protontricks installation method: Protontricks with graphical interface available in the discovery store
• Protontricks version: Current version
• Steam version: Last current version (no beta)

Additional context
I then tried with a 32 bit prefix and this time it worked as expected without any problem, no error, dotnet40 is displayed in the “uninstaller” menu as expected and I no longer get an error when I launch GTA4 but the game crashes when I start a new game (the “new game” at the bottom right of the screen continues to be displayed non-stop). I think this is due to the fact that GTA4's minimum requirements are windows 10 64bit and not 32 bit (because of rockstar game launcher...)

I know I can downgrade the game but I don't want to take the risk, I'd like to play on my steamdeck with the complete edition (especially since I have fusionfix and I'd like to keep it).

In mod I also have FusionFix, ConsoleVisuals, VariousFixes, Radio Restoration. The .asi loader that goes with FusionFix and a patch to make scripthook dotnet work with the latest version of the complete edition.

Link to youtube video to install the first 4 mods on steamdeck (by TJGM): https://www.youtube.com/watch?v=T_UIMKd9wqw

Link to the reddit mentioning the mod for the .net patch for complete edition (the mod link is available in the message): https://www.reddit.com/r/GTAIV/comments/gkqgiv/you_can_still_use_mods_on_the_complete_edition/?rdt=37482

I use proton experimental to run the game and I have this in steam launch option :

If I use a 32bit prefix :
STEAM_COMPAT_DATA_PATH=path/to/prefix/ WINEDLLOVERRIDES=“dinput8=n,b” %command%

If I use the default prefix (64bit) :
WINEDLLOVERRIDES=“dinput8=n,b” %command%