I agree, video conferencing on NethServer would be awesome!
Just to know, our friend of nextcloud are going to offer spreedbox!
We did have a look at blab. It has very nice features and both video and audio are better than hangouts. But as hangouts, it is not avaiable as a package that you can install on your own server. Maybe you can create something like a webportal that connects to blab?
Just to add some other conferencing software to the list:
Really, in the current COVID-19 situation, I would love to host some video conference System - Please … push it.
Current efforts are towards Matrix-Synapse (with jitsi)