Blocking AI Notetakers

We're struggling. People keep going out and signing up for things like read.ai or otter.ai , connecting it to their calendars, and then the notetakers are auto joining meetings.

It's against our policies, so that's being addresed, and we got approval to actively start blocking these things but we can't seem to get it blocked or removed from meetings.

In entra, we've removed and deleted the enterprise app registrations and blocked users from self registering things. The apps are blocked in teams. Yet still they persist. Somehow.

Can anyone offer some way to completely removing these things?