I see a big error to call messengers like Telegram or Signal to be "anonymous" when they require at least an active SIM card to set up an account

Getting an anonymous SIM is impossible in most countries now

The most salient property is probably governance model and diversity of funding. Telegram can be leveraged easier because it is privately owned and top-down. It is harder to pressure an elected board esp. if members are in different countries. The technical component has to be solid, but that doesn't mean much if one person controls everything; c.f. the xz backdoor.

I'd suggest replacing the 'anonymous' column with 'requires PII'.

I prefer Matrix, but haven't heard of some of these.

You're missing a very important column: Is it possible to join the network by running your own SERVER?

Any network that depends on a centrally controlled server has a single point of failure. (Yes, this is a recommendation of Element/Matrix.)

Also, ideally, identities should be possible to migrate like they (sort of) are on Mastodon and friends.

signal is not anonymous. The phone number can be associated with your name.
I think part of the evaluation process should be the location of their servers.

Teleguard from swisscows has absolutely no association with your phone number and their servers are in Switzerland.

certainly no telegram, if possible. but it became more than just messenger, unfortunately.

if it should be a channel, i guess matrix kinda works. maybe with Chinny client?

if (open) group chats, matrix as well. also signal, but the problem with signal is that it requires phone number (even if you can hide it).

if private messages, signal and matrix; simpleX seems nice, even though i didn't try it. threema is not free, so not everyone will be able to use it.

signal and matrix have their problems, but they're WAY better than telegram kremlingram.

don't know about wire and session much, can't really say anything about them.