Signal is a secure messenger that is widely touted as one of the best options. This Signal review shows you the pros and cons.
"When you use Signal, your data is stored in encrypted form on your devices. The only information that is stored on the Signal servers for each account is the phone number you registered with, the date and time you joined the service, and the date you last logged on."
This isn't an ad, I wasn't paid for this post. Just to clear the air: fuck facebook, fuck elon musk and twitter, fuck anyone who thinks this is a paid advertisement. I wish I was paid for this shit, I just wanted to spread the word. Thank you. 😀 👍
They are ignoring a lot of cryptographic best practices in their protocol to the degree where anyone taking a basic cryptography class will laught at it. The paper above shows that some cryptographic properties can be proven for telegram but those look more accidental than actually planed.
So yeah I'd say telegram is way more sketchy. The signal protocol is significantly better. Telegram's still probably better than WhatsApp tho.
Also, while I'm not familiar enough with cryptography to know how accurate that is, speaking to OP's point regarding the people behind the apps...Telegram's people are sketchy themselves. From what I gather it sounds like the lead person behind Telegram is more or less a tech bro but Russian instead of American or South African, and has some similar negative qualities.
It's a long article, but Wired's feature on Telegram is an interesting read. TL;DR though is that Telegram seems to be led by yet another eccentric libertarian who reportedly is very controlling over certain aspects of the platform.
As an aside, for anyone put off by Signal's foray into cryptocurrency BS, Telegram also tried to dive into crypto, so...Yeah.