I write all of my openapi specs by hand. It's not hard.
A sibling comment to your reply expressed the same sentiment as me, and also mentioned typespec as a possible solution
There is the part where dealing with another tool isn't much worth it most of the time, and the other side where we're already reading/writing screens of yaml or yaml like docs all the time.
Taking time to properly think about and define an entry point is reasonable enough.
I think you're over fitting your own experiences.