With SaaS apps, I've found you either have to hand write a framework for it to use, or put an even greater amount of effort into double-checking and correcting it. Then you can point it at bugs and features, get it to write tests for you, and so on. If the code's too wordy, who cares? Keep the blast radius to self-contained modules and the AI can't mess up too badly. Whenever you abstract something or the work is critical, you need to go back to hand writing everything.

Abstractions are like the structural elements of a house, security is like plumbing or electrical, but individual features are like carpet and paint. When it's working on the superficial stuff, who cares what it gets wrong? Just go rip up the carpet and do it again if you have to.