Complete the mail bridge. Add Webdav and LDAP (or whatever) to bridge for contacts and Calendar
Complete the mail bridge by adding a tunnel or something through which a local client can manage contacts and Calendars.
Mauro Gaspari commented
I agree with this. I have to rely on nextcloud calendars and contacts sync because Proton Mail bridge is unable to handle calendars and contacts.
I currently have to use a nextcloud server to manage calendars and contacts, because of the lack of this feature (and lack of contacts sync on mobile). It would be much easier to be able to just sync email, calendars and contacts via Proton Mail bridge.