Just as background: I’d started using Steam Remote Play and streaming since it first was released, and though I don’t use it much these days, I did get through the infinite loading by launching windowed.
The other workaround I used to employ frequently was launch another game that’s easy to switch windows out of (I picked a free point-and-click adventure game I had), then launched the app I wanted to use, browser, game or whatever, through the normal desktop environment. Just as a test, see if that works for you. In my experience in the earlier days, I ran frequently into problems when my host machine was running without a connected display, but maybe things have improved over the few years it has been out.
Also your system is Wayland right? Are Switch emulators running through Wayland or Xwayland, and Cemu not or vice versa? Could that have something to do with it?
*Some google-fu leads me to suggest prepending QT_QPA_PLATFORM=xcb to the launch command (as a Steam shortcut you would have the launch arguments be QT_QPA_PLATFORM=xcb %command% )











Lemmy’s search, rediscoverability of older threads has a few things left to be desired, and deleted posts make the comment contents very hard to found, but overall it prioritizes persistence against censorship and archivability over keeping communications private and ephemeral, which is what I like about it.