I almost exclusively use desktop mode. One of the main reasons I got a steam deck was to have a Linux PC connected to my TV at all times. I watch a lot of sports via pirated streams, and those only really work well in a web browser. A raspberry pi 4 was not quick enough to keep up with it, but the steam deck is more than capable.

Setting up emudeck

I mostly use desktop mode for messing about with things like emudeck and creating and forgetting an su password.

Currently, just when I have to use it to install anything that I can’t install via game mode, and when I need to tweak the system or game files, copy roms from my NAS, etc.

Mostly installing games from outside the steam shop.

Not frequently, I tried to use it to launch gog games via lutris but they were not performing as well as within the steam app.