So my friend group has been looking for alternatives for a while now that feel like discord, works on mobile and desktop, and has voice chat.

I use Signal but the UI is very different from Discord.

I've had very mixed experiences with Element + Matrix, Element keeps crashing on mobile, and while voice chat kinda exists in Element it's not been great imho.

I looked into hosting Rocket.chat, Zullip, and Mattermost but from what I recall voice + mobile were either missing or paywalled at a per-user price.

Any recommendations?

I seem to recall Jitsi working pretty well.