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.

NewPipe SponsorBlock

https://pastebin.com/gxfm3J7b

deleted by creator

Ferdium does this and it’s open-source. It supports Lemmy too. And you can even add your custom website.