session is better than telegram or signal because you don't need a phone number to register, also all traffic is routed through tor so your IP is hidden, personally I don't trust telegram at all (same issue as whatsapp with it being closed source) and signal is alright I guess but session's the best
In computer science, a session identifier, session ID or session token is a piece of data that is used in network communications to identify a session, a series of related message exchanges. Session identifiers become necessary in cases where the communications infrastructure uses a stateless protocol such as HTTP. For example, a buyer who visits a seller's website wants to collect a number of articles in a virtual shopping cart and then finalize the shopping by going to the site's checkout page.