Matrix/element is the best bet atm. Had a solid 40m users compared to Discord's 140m at some point, which is good proof they can scale up compared to other. Hardest part is convincing your groups to switch from Discord. But you can bridge the two in Matrix and talk between them which might help ease the transition.
Teamspeak has been drama-free at least and spared from bigtech bullshit, but simple things like changing your username havent been working for like 6 years now, it is in rough but ok shape if you want a drop-in replacement. You can freely make group chats and categorize them by right clicking them to create Discord-style chatrooms or voice chat rooms. Otherwise you must pay to set up a Teamspeak community for your friends.