Check out Exodos for this type of thing. It's built on launchbox (an emulator front end) and just gives a huge listing of every game you might ever want to play. Those games aren't all installed (assuming you didn't do the full 500GB+ install) but you click the game and it quickly downloads, installs into dosbox and jumps into the game (takes seconds since these are old games).
Slightly related, if like me you have gone far to far down the emulation rabbit hole and find that you are now onto FPGA emulation, you might enjoy:
https://0mhz.net/
https://amiga.vision/
I really want to get these working on my steamdeck too but it looks like a lot of work.
https://www.retro-exo.com/exodos.html