If you live near a college campus, check out their recycling center or campus surplus. Lots of IT departments just toss UPS when they upgrade equipment regardless of battery status. I like to grab APC ones because the battery replacements are easy to find and there’s usually a YouTube video for the exact model with someone refurbing it.
I just bought myself a Bambu P1S, after building and modifying ender3s since 2019. I love tinkering and customizing things but it’s nice to have a printer that just works. Its so reliable that my wife can now print her own stuff using the app instead of giving me a list. The only thing I really have to do is change the filaments loaded in the AMS for her. If you have no experience printing I would just get a A1 mini and use it until you run into the limitations.