Signal routes all messages through a Signal owned and operated server so they see who sends and who receives each and every message. And account creation is tied to your phone number, which is likely tied to your true identity, with some financial info as icing on the cake.
Their system is not federated, you cannot run your own inter-operable Signal server.
For a more private way to communicate, use https://delta.chat/ with a mailbox from https://nine.testrun.org/ and enable access via Tor.
First, welcome to the forum, I hope you enjoy your time here. 
To respond to your comment, what source do you have for the claim of “they see who sends and who receives each and every message”?
This is true but it is also possible to have a number that is obfuscated but yes, phone number association is a problem for me which is why I never gave out my Signal data publicly.