Honestly I have really fallen in love with using normal programs fullscreened through steams gaming mode. It feels like a natural evolution of a window manager like i3, so much new stuff to learn and the exciting thing is this is all new for everybody!
Also in the realm of space games, Overload is a BLAST on the deck, especially in short bursts. It is a great way to quickly get locked into the Steam Deck for high intensity flying and fine aim control.
I would like to suggest a perhaps oddball steam deck utility here.
logseq!
logseq is a note taking, thinking and task tracking tool, it is open source and free and works superb on the steam deck when launched in gaming mode.
https://logseq.com/
logseq has functionality for
-arbitrarily deep trees of headings
-easy linking between pages (think wikipedia)
-calendar and in depth task tracking and scheduling
-whiteboard simple visualization utility that can link back to notes
-ability to reference specific parts of a pdf or image from notes and link directly to it
You can then use the equally superb and also free and open source file sync software Syncthing to sync your logseq notes between different devices (say your phone and steam deck).
https://syncthing.net/
Using these two utilities you can easily build a cloud based task tracking and note taking system that has ZERO percent lock-in to any corporate silo or any subscriptions, you have complete agency over the whole thing and its pretty damn slick too!
Logseq notes are stored as plain text markdown which adds an extra layer of comfort in knowing if you take a bunch of notes on your games even if ALL development of logseq somehow went belly up those notes are stored in plain text markdown… so you arent going to lose them/have to rewrite them by hand.
(your notes being stored in plain text also means that even a comical amount of notes takes up only kbs of disk space)