Have not implemented it but would recommend Jitsi or big blue button. If you want to have a discord experience maybe also revolt chat

There is also matrix and nextcloud has the talk integration (also based on the fediverse Afair)

Skype for business? /s

Mirotalk might be an option:

https://github.com/miroslavpejic85/mirotalk

Federated Computer offers hosted Jitsi and Element/Matrix (and a ton more) at https://www.federated.computer for $39/month/domain. Maybe that’s a fit for you?

zulip/jitsi