And if so, how?
Absolutely, I played it with about 4 mods entirely on the Deck.
You just place the mod files on the Mods folder for the game, I recommend using SSH and FileZilla for this.
Some mods require a specific config file to be modified depending on wether you play the DX12 or DX11 version, you can just follow the instructions provided for Windows by the mod creator, its exactly the same.
I do not recommend trying all these bloated mod manager tools, these might actually not understand the folder structure correctly on the Deck and create issues.
I did, for the enemy scaling mod. It requires making a “Mods” folder in the Witcher folder, and the copying the mod there, no further work. Was easy enough to do in desktop mode with the GUI
Modding on Linux is generally quite complicated I find. Some games may be easier than others but they usually require some launch parameters.
Some of it can be, I agree. Some is really easy. It really depends on the game (I can’t speak for Witcher 3).
Sometimes it’s as easy as creating a mods folder in the game directory then downloading the mod and moving into that folder.
For Bethesda games, I’ve used rockerbacon’s mo2 script and it works well. For other games, I just follow the install instructions manually, however I have encountered some limitations here. Mods that require a program to modify files (eg, texture replacers for the Dark Souls games or to merge mods that alter game_main.arc in Dragon’s Dogma) have been a no-go for me so far. There have been convenient work-arounds for some instances (Dragon’s Dogma has some mod-packs that include all or most of the individual mods I would’ve wanted, so I just install that).
And I’ve definitely encountered a number of mods that require a launch parameter for dinput8.dll (and I think one mod required a parameter for some other dll, although I can’t recall for certain); finding this out the first time I encountered it was a huge pain and I only found the answer by reading the forums for another mod on another game. Now that I know about that particular issue, it isn’t too bad but it absolutely made the first time modding on the Deck more complicated than I had expected.
The dll overrides can also be set with the windows style control panel from wine if you open it from the games prefix, but generally the launch options is just the easiest way to explain to others