Oddbean new post about login | logout I disagree with this chart. I think 1, 2, and 6 are all on the same level when properly implemented.
However, we need to consider that in large group chats, such as those with 1000 participants, updating the key tree results in 10 updates per message. Therefore, achieving the same frequency of updates as in one-on-one or small group chats is quite challenging.