

FYI, Bazzite has an image specifically made for GPD handheld PCs, just select it from the download list. I don’t have a GPD device to test it on, but their flavor for ASUS has the ASUS specific utilities installed and already set up, so I imagine the GPD image is the same.
I have the ROG Strix G614. I can’t really say I’m missing anything, because the ROGCC app which replaces Armoury Crate or whatever it’s called on Windows covers all the usual stuff, and there was no install procedure because it’s already hooked up with the things it needs to work.
In your case, the utility you would be using for GPD is Handheld Daemon.