Nothing new here. E2E is only available in one on one chats and is disabled by default. Dont use Telegram if privacy is your main concern.
At least it has an open-source client. Very few messaging platforms can say that, and fewer have a decent UX.
It's not perfect, but it's got a good combination of features and multi-platform availability. None of the other messaging apps support all of my devices except Matrix, and ~~Matrix doesn't have stickers~~
Edit: Signal doesn't support all my devices but maybe someday! The network effect is also big. None of my family and friends are on Signal, but most have Telegram. A few have Matrix.
Also Signal is a US-based company.
Edit 2: Matrix does have stickers, i guess I'm switching