Telegram does have E2EE, just not in regular chats. Its secret chats are E2EE, as are its voice and video calls.

I also think it has the best UI of any of the messengers, personally. It's customizable and very polished overall, at least on Android. Very smooth/optimized while having loads of features and lots of little animations to make things flow nicely without getting in the way.

I do like Signal and Matrix clients as well, though I just wish Matrix had more of a user base.