I also use Simplex, but you see, a messaging app has the purpose of... messaging people.
Basically, no one uses Simplex (a part of a few selected chaps here on the forum).
There are a few outstanding apps out there (I like Keet.io very much), but if nobody uses them, there is no point.
I know what you are saying but once upon a time nobody used telegram, and before that nobody used viber, and before that nobody used skype, etc.
If you want to continue using telegram than you have to agree with their terms and accept all the risks,
just keep in mind there is zero privacy with telegram app, and everything you wrote including used phone number can be leaked one day.
I am basically on every chat platform and messaaging system (bar Whatsapp). What I mean is that i stopped being pushy about moving people to new network.
I have various degrees of privacy. If a conversation is partuclarly hot i move to keet.io, or Simplex, otherwise I stay on a more widespread application.