Anecdotally I see this _all the time_...
When you are an experienced developer and you "struggle" writing manually some code this is important warning indicator about project architecture - that something is wrong in it.
For such cases I like to step back and think about redesign/refactor. When coding goes smoothly, some "unpredicted" customer changes can be added easly into project then it is the best indicator that architecture is fine.
That's my humble human opinion ;)
When you use AI to generate your code, instead of you writing it and then someone else reviewing it, there are two people reviewing it (you and the reviewer), which obviously takes longer.