I’ve got a lot of mileage out of Pocket City 2.

Side by side pic here. I was quite surprised at just how small this thing is, and if the Miyoo is even smaller, I’m glad I opted for this!

The screen is indeed very nice.

Hundreds, if not thousands, across all kinds of retro consoles! Atari all the way through Gameboys, NES up to PS1. The default OS seems ok, but I only tried it briefly before switching over to GarlicOS which everyone seemed to be keen on. This guide was super helpful in getting me started.