I have 15+ years of experience in software development. The hardest thing I had to learn recently is that paring with AI changes the definition of "what is hard". You can decomposit a refactor into a steps of two kinds:

1. Conceptually hard, which you have to really think about and write code by hand for AI to follow,

2. Time consuming that follows patterns.

Then you do 1. review with AI what are implications on the codebase. Next you crate list of task for 2. and keep reviewing outcomes.

This does still not include any QA. The fact that A.I. tells you the implications of your changes does not take away the effort and time you need to verify the correctness end to end