I've done the update a while ago and it went pretty good. Only one minor issue that took all but 2 minutes to solve, so ultimately I think I've spent no more than half an hour getting the whole upgrade done.
The only real issue I had was with postgresql, more specifically that their package repos had changed urls and keys, so I needed to update those. They automatically upgraded with the rest of the system to grab fedora 40 packages. So now I can keep running postgres 15 until I have time to properly upgrade to 16.