When I was booking our FP+ selections this morning, there were many cases where Disney's best option (and even A, B, C options)
overlapped with an existing ADR. It even noted this for me on the FP+ selection, not that I wasn't aware since I made these ADRs back in March. I found the easiest way get everything how I wanted it was to pick three attractions, let
MDE pick the times, and confirm. Then, I immediately went back in and moved everything around to times that actually worked for me. It seems like they could do something to streamline this process.