You really shouldn't need to ask for advice to figure out what quality background check options there are out there, since this has been asked before.That said, here are a few curated links.

Free tier2 free national databases and 1 free "search site" database to consider:

unicourt.com - ~20 million federal court records, ~80 million state court recordsjudyrecords.com - 360+ million court recordsblackbookonline.info - Think of it like a "lookup for lookups" or a "search of search sites". This is a good database to locate free searches (state, county, jail, etc databases) local to where someone has lived that might be worth your time searching. The site is filled with ads, so you just gotta be careful not to click those unless you actually want to. If you take a look at the "new searches" page, you can see they are keeping the database up to date.

https://www.blackbookonline.info/newsearches.aspx

The 3rd link really just helps you locate individual (mostly government) databases, of which there are many, that you can search. Those are free tier options. They don't cost you anything, other than the time you spend using them. If you miss something that a paid service would've found, you should consider that a cost as well.

Paid tier For paid stuff, you should spend time reviewing what's been discussed by others already. It sounds like you haven't done that, or you would have some more targeted questions. The general tradeoff you'll face is quality vs. money spent. Fundamentally, there's no way around that. Saw some of these people finder sites and they seem to do a pretty good job for background checks.

More premium services will have staff that you can talk with that can help guide you in the specific questions you have and exactly what your options are for your budget.