Okay, just clarifying that you don't mean the Beeper server, you mean the beeper desktop/mobile client. You can self host something identical to the server and use a the client that Beeper's client is based off of, which is very similar.

Self-hosting may become even more like using Beeper's server and client soon, as I expect they will not continue development on the old android app and just work on the one currently in beta. The beta app feels pretty similar to element to me, so I'll likely self host when they do that.