SimpleX has the best privacy, because of removing metadata.
Signal comes close, and has many more users. Probably some of your friends already use it.
If you want something similar to Telegram/Discord/Slack, then Element (Matrix) is what you’re looking for.
All of the above are E2EE.
I just found this. Haven’t tried it.
https://www.f-droid.org/packages/com.burhanrashid52.photoediting/
Try https://simplex.chat. Better privacy and no phone number required.
Most cryptocurrency communities use Discord or Telegram. It’s such an embarrasment.
If I understand it right,
Please correct me if I’m wrong.