Any idea if it’s self host able if it’s open source?

Telegram is absolutely not vastly better than WhatsApp. Open Whisper Systems literally built the E2EE in WhatsApp. Its implementation of OTR predates signal.

Meanwhile, Telegram insists on rolling their own crypto and it’s closed source.

I think OP can and should try to get friends into Signal. But WhatsApp I’is almost certainly the answer to the OP. It offers well implemented proven off the record, E2EE communications, it’s widely adopted, cross platform. It’s miles better than SMS and Facebook or Instagram messenger or Snapchat. OP is looking for the best compromise, WhatsApp is it.

Say it with me: “Enshittification”

Fan of OTP Auth

How young are you? FUD did not originate with Crypto. And crypto-means-cryptography-fight-me.