I replaced Discord(and Whatsapp) with Matrix/Element as voice chat (and general chat) with my wife. I remember running it with Docker was bit annoying to set up (I was selfhosting beginner when first doing it now it could be easier), but with Yunohost it is one click install (if you are willing with swap operating server).
Nextcloud Talk could work for your needs, but I have not personally used it so hard to recommend it.
