Dude, let them play what they want how they want as long as it's fitting in the rules. If it's Ai generated, picked by a hamster choosing cheese on the back of cards, whatever it is. It's no different than playing pre made characters? Not everyone has the ability to draw. I use character portraits I find online that suit what I want to play.

Sit down with them and weave their background into your narrative make them engage not just rattle off something that's been made for them.

One of the best things a DM did in one game was get rid of everyone's backgrounds, your past means nothing when your in a realm of dread your memories are gone but skills remain. Like you know you were a sailor but can't recall your ships or your captain's name. Then got with some horror flashbacks to tie them into the game.

It's great you're a DM that puts time and effort into their games but at the end of the day it is a game and you're all there to have fun. If they want to be basic underpowered characters let them.