TLS already has algorithms hardened against QC. The effects of QC against encryption are greatly exaggerated, anyway. The number of qubits that would be needed to break encryption may be too large to ever be feasible.
Get IPv6 going and stuff like SNI becomes unnecessary.
Headline is terrible. The big red flags are that they don’t do end-to-end encryption by default, the servers are in Dubai, and use a proprietary algorithm.
Last part should be clarified further. They didn’t reinvent AES or anything. It’s more like a protocol that puts together existing algorithms. It means they can use transport layers without TLS or anything else that wraps your messages in crypto otherwise.
https://core.telegram.org/mtproto
I’d still say this is a red flag. How you wrap encryption around your messages has several pits you can fall into. It’s not as bad as reinventing AES, though.