Regularly, I use the following for near-realtime communications ("text messages”).

- SMS/RCS/iMessage (friends, family)
- Facebook Messenger (friends, family)
- What's App (friends)
- ActivityPub/Mastodon (friends)
- Matrix (friends, work)
- Discord (work)
- Mattermost (friends, locals)

I'm sure I'm missing some.

The fact that no one is allowed to make a single piece of software (for wide distribution) that talks on all of these systems is the kind of garbage @pluralistic often talks about.