I'm also wondering if this used to be/is a thing in settings. One thing I noticed is that when you start recording a meeting, the UI shows an elapsed time next to the recording symbol. This time seems to reflect the amount of time since the meeting was started. This has me wondering if at one point in time, teams was designed with this capability in mind. However, the more I think about it, it would sort of violate people's privacy. You'll notice whenever you start a meeting, it tells everyone on the call and has them dismiss the message. This 'informed consent' can't really work retroactively, though, because it would be recording things people said under the expectation that meeting wasn't being recorded.
All that to say, I wonder if Microsoft is being coy about this feature ever existing, since, if it did, that would have been an oversight.
