Session is also sus because you effectively cannot host a node, last I have seen. They claim it is “against a Sybil attack” but all it does is making sure only people wih large disposable funds can have nodes, and the effect might be the exact opposite.
Simplex is more interesting in this regard because while I am concerned with initial centralization (the default servers), they made hosting your own easy. But I personally stick with imperfect yet trusty XMPP.