TIL that Snapchat is an app used in 2024 without E2EE, Wikipedia article on Snapchat :
Encryption
In January 2018, Snapchat introduced the use of end-to-end encryption in the application but only for snaps
(pictures and video), according to a Snapchat security engineer presenting at the January 2019 Real World Crypto
Conference.[138][139][140] As of the January 2019 conference Snapchat had plans to introduce end-to-end encryption for
text messages and group chats in the future.[141]