Example, WhatsApp, use the whole 25 character profile name limit:
Bob Moved To Signal.org
Alice MovedTo Signal.org
CharlieMovedTo Signal.org
Say Signal.org, not Signal, so they see it is an app.
Use your about section too.
Same on Discord, Steam, Instagram, everywhere.
You don’t need everyone. Just start somewhere. Start now.
To be ingrained, it had to get ingrained but you can do that too!
Pick two friends and make a group chat. Others will feel left out and want to join. It only gets easier.