Signal is getting better. Maybe someday they'll support Telegram's features like pinning messages and large rooms. But they are a good alternative already if all you want to do is chat and share memes.
You can sign up and use a fragment number. Requires you paying in the telegram crypto TON, then registering that number during account sign up. It's not a real phone number and can't do sms or be used with other service, but it will get on you telegram without giving up your real number.
They do have to, we are literally living the era of Cambridge Analyticas and troll factories that proves why. Imagine tying your phone number to Twitter's app just to be classified as a troublemaker and persecuted in things like job searches just for disagreeing with Musk, it's closer to reality than you think.
You have to be on at least some, right? I'm pretty hardcore about the hacker lifestyle and I still need to be able to open a new email account, get certain government services (although I guess most will do everything by snail mail) or communicate with certain businesses.
There's no good reason for a messaging service to work based on them, though, you're right. Signal I'm looking at you as well.
But am I fucking going around on Telegram in child abuse or trafficking rings or some other shit? Am I part of the child pornography ring or some other shit? Get the fuck real, you moron.