Find a workaround for teams external access, while you are trapped in SFB Onprem with Island mode.
VIDEO SPOTLIGHT IN MICROSOFT TEAMS
Video spotlight feature will be available for GA by Sep 2020 which is a long awaiting by Teams customers.
Microsoft Teams+Translator = Break the Language Barrier
Use Microsoft translator to enable non-English speakers to be in conversation.
EXTERNAL TEAMS MEETING JOINING EXPERIENCE FOR USERS DISABLED VIDEO IN THE OWN TENANT
Teams meeting policy restriction and its impact