I know this has been mentioned before, but it’s worth mentioning again as 3.5 is released in Stable channel. There is a Nested Desktop app you can add to steam from Desktop mode. This will allow you to manage desktop files and use apps from within gaming mode, without having to leave gaming mode. Desktop works just like another game (app) in Steam.
In the Application Launcher, search for “Nested Desktop” and add to Steam. There are community controller profiles, that you can use so that you can use trackpad and navigate easily.
I love that this is an official feature, but it’s straight up not working for me. It switches to the Steam Deck logo with the little loading circle at the bottom and it stays frozen like that forever, no matter how long I wait.
Be aware that Nested Desktop will crash under some circumstances. Not sure why, but it crashed for me when I installed an app in Discover.
Also, Steam ROM Manager needs to kill Steam when it adds the shortcuts, but Steam itself is running the Nested Desktop session, so trying to use ROM Manager from Nested Desktop is probably a bad idea.