Been great for me but I have had to clear config a few times to get settings to stick. Been mainly playing switch/with though, haven’t tried GBA. I have done writeups years ago on manually setting up emulators/steam rom manager, so I think they’ve done a great job automating a lot of it away… But at the end of the day it’s still a fiddly proposition

I also only got my first deck last month a d went through a similar though.

I’d suggest:

• Play with it a bit stock. It’s a great experience and you really don’t NEED more.
• If you have any interest in playing older consoles, Emudeck is an amazing experience and worth it for the ‘oh wow’ factor
• Add Plex / streaming though flathub/discover and add to steam for travel streaming
• Consider decky for a few QOL menu additions
• For pick up and put down games review threads on indies for games you’ll love. Balatro, Hades, Dave the diver, dredge, undertale, into the breech, FTL, the list is quite long and there are utter gems, but it will be dictated by what you enjoy