what I'm saying is that Fed hikes interest rates → bonds sell off → yields rise → mortgage rates rise.

This is logical and empirically observed.

But you are right on the longer term effect. Zooming out: Fed hikes → inflation cools → inflation expectations fall → yields fall → mortgage rates fall.

But the latter is not guaranteed, and it takes time.

I'm unsure to understand how the ceiling and floor mechanisms work. But will dig into that. Thanks.