I use Telegram every day, but without end-to-end encryption (by default and on groups), it's as private as Facebook Messenger. They can read everything. The only difference is that currently people trust them more than they trust Facebook, but everything turns to shit eventually.
If Signal is too "boring" or no one uses it in your circles, try WhatsApp. Yes, it's also from Meta, but at least comms are encrypted (same protocol as Signal) and a lot of people use it.