Personally, I prefer jitsi.
The vicol example here Nextcloud App for BigBlueButton integration is a very good example.
Jitsi also uses APIs.
Jitsi can be integrated into RocketChat:
https://github.com/jitsi/lib-jitsi-meet/blob/master/doc/tokens.md
https://rocket.chat/docs/administrator-guides/setting-up-video-conferencing/
Maybe take example on rocket chat, and use this token authentication method for nextcloud?