The Telegram protocol I’m so critical of was v1 which included DH, RSA, AES in IGE mode, and SHA1. All used in random ways with key sub setting, reuse of some key bits for multiple purposes, etc.

https://core.telegram.org/mtproto/description_v1

I honestly haven’t looked into anything newer from Telegram because it was pretty clearly a tire-fire and Signal was already a thing.