I cannot change mine from “always allow” either and do not have or ever had any organization associations. It us a brand new 17 that is my own device as transferred from last iPhone. Both have iOS26 running. I see now that phone is also locked on “always allow” and shows the “..organization…” message. The old phone has likewise always been my personal device never associated with organizations or profiles. There are no profiles on either phone.
This seems to be a problem beyond normal MDM profiles, I have seen other reports online that it could be a bug or it could even be hack.
Without any other information here I guess the next step is the Apple Store; at least before I go nuclear and install everything from scratch.