You could always roll your own protocol that you use to interface with contacts, basically replicating Signal's algo. The gov wouldn't be able to stop that.
The Signal client and (irregularly) the server are published as open source. You can run your own Signal instance. If you want to complicate your life, of course.
There is an easier way - going with a selfhostable, federated solution. And at least XMPP is now commonly used with an encryption protocol that is based on Signal's.
They poke a hole in signal and all secure messaging /communication is screwed. it wont matter what "other" product you use.