You mean text editing after sending? I would definitely not consider that a "basic" feature - we are talking about E2EE here, editing a message that you already encrypted locally and then sent on its way is by no means trivial - especially with the kind of E2EE that we have nowadays.
It actually is super easy, barely an inconvenience. When you edit an E2E encrypted message, your client simply sends another E2E encrypted message telling your contact what to replace your previous message with.
I like Threema a lot, but it lacks basic features such as text editing, so I can't imagine recommending it to anyone.
How many contacts do you have in Threema though?
Only one that I actually talk to
You mean text editing after sending? I would definitely not consider that a "basic" feature - we are talking about E2EE here, editing a message that you already encrypted locally and then sent on its way is by no means trivial - especially with the kind of E2EE that we have nowadays.
It actually is super easy, barely an inconvenience. When you edit an E2E encrypted message, your client simply sends another E2E encrypted message telling your contact what to replace your previous message with.