Is there any way to verify how many servers Session is running?
I don't think they're financial model (shitcoining) is working out for them and oxen is running them all.
I run my own Simplex relays.

AND they're not using double ratchet encryption. intercepted messages can be decrypted if an adversary gets access to the sending device.
Simplex uses model Signal encryption.

so a small number of servers run by a single entity not using modern encryption.

doesn't sound very secure to me.
I'd prefer a organization with a viable financial model.