Proton Meet Isn't What They Told You It Was
https://www.sambent.com/proton-meet-isnt-what-they-told-you/
Proton built Proton Meet to escape the CLOUD Act. They built it on CLOUD Act infrastructure. Their website promises "not even government agencies" can access your calls. The company routing them hands your call records to the government when asked. Proton hid them from their privacy policy.
After Proton has repeatedly turned over users of their email account to law enforcement, always with many excuses, their claims about no ability for any government to see what's going on on their network ran very hollow.
I know Brave has offered their talk video conferencing service for awhile, but I don't know if any serious network analysis has been performed on it.
https://talk.brave.com/
For document collaboration, I'm not aware of much else that's private/encrypted (etc) however.
https://www.privacyguides.org/en/document-collaboration/
bundie