You just let him walk and didn't call the cops?
Especially in a small company, sometimes it’s best to cut your losses quickly and toss the rotten apple over the cliff rather than go out of your way to stomp on it and deal with rotten apple stuck on the bottom of your shoe.
Definitely not a 10x, just a scam artist.
Did you only fire him because you found out he worked other jobs or because he didn't do enough work?
It’s not so much about whether he was a good coder. More that I can’t trust someone with production database access if I discover 6 months in that he has 2 other full time jobs.
(He was also not doing an amazing job - he required constant supervision without which he wouldn’t produce any meaningful output, presumably because he had 2 other managers he was trying to please at the same time)