If you have encouraged someone to switch to say Signal, or Sessions, or XMPP or some other tool/protocol, please share here.
I need as much success stories as possible.
----- Anonymity is guaranteed if requested, you can use my Sessions messenger session: 0531634331f5b6be12375bf4229412eed3f2f3543cfe119df37e1b72c883143d4a
(That's how I've gotten a lot of folks on Signal: "It's like PGP, but usable." The phone number thing was a hangup for a while but with the usernames feature, that's gone.)
How vigilant people are about privacy will vary greatly by generation and by group interests.
This goes back to the variation by generation and group interests. People that already feel oppressed by the main platform may likely stay on the one you provided them, otherwise most will go back to whatever they and their friends liked about their main platform. Unless these people are your employees it is unlikely you would be deciding where they go. Even in that case employees will do what they can do.
Ask these people what they like about the platform they are on and decide if you can replicate or enhance that experience. If you can, show them and they will decide if what you created is something they would prefer.