The founder of Nextcloud @frank Karlitscheck has expressed support for a new effort to write an open source Nextcloud Talk backend server alternative and has offered help:
I suggest @ramezrafla and vicole ping him directly to ask for support for the Big Blue Button integration as well. Given Nextcloud’s new partnership with Ionos and Viakom to push Nextcloud as solution for schools and SMEs there should be enough synergy to make this interesting for them:
Nextcloud Talk is based on code done by Spreed, a company that is keeping the High Performance Backend to Talk closed source and is asking huge license fees for it . So its just not accurate to imply that Nextcloud is benefiting from the fact that the High Performance Backend is closed source