I’m hosting fluxer and matrix, but fluxer is fantastic. One consideration, for some reason the documentation doesn’t tell you that you need to go to the admin page, create a voice region, and a voice server, to actually use the voice chat that’s part of the guide.

If you want a mature ecosystem, try out matrix, although it is much harder to figure out how to host it.

If you want something that’s intended to be a perfect discord replacement, go with fluxer, they did an amazing job with the self hosting guide.