I know someone that has a Beelink mini PC and is happy with it, and I’ve heard some good things elsewhere too. I’m probably going to get one once my current Lenovo mini goes bad on me. They have some sub-$200 USD options that I think can fit two m.2 SSDs in them.
It is an enjoyable way to contribute to the OSM project! I mostly use JOSM or the iD editor for mapping, but when I only have my phone I’ll pull out StreetComplete and do a few quests.
For beginners to mapping, it’s a very easy way to contribute without the worry of messing up something!