Cannot move folders in Mail on Mac

There is much griping about this issue online and no solution. I spent hours on the phone recently with customer support at apple and still could not get it to work after much technical tweaking. Then I was promised a phone call from someone with more expertise that never materialized. So maybe they could post a solution here? Just for reference, my Mac is a Macbook Pro, 2021, 14 inches running Ventura 13.1. Interestingly, my old Macbook, 2018 13 inch running the same OS has no problem moving folders. So I'm at a loss...