I'm not the person you're replying to, but I have a lot more confidence in my own 20k lines of code than an AIs. I've built up skills to write performant, readable, functional, maintainable code. I build it up slowly and I can anticipate bugs as I write. I'm not perfect, but when bugs do arise, since I've built up the code, I have some idea of where to look and where not to look in order to fix them.

As for coworkers, I would really try to get them to work in chunks smaller than 20k loc. But at some point you have an expectation that coworkers will be accountable for their area of responsibility. If there's a bug in their code, they're expected to fix it. If there's a bug in the AIs code, I'm expected to fix it....