Detail in mobile notifications like location, end time, and who's calendar event it is via there email.
And changing the notification time it was recieved to the time the event is happening.
Also add icon options to events similar to proton pass groups.

See example image below, comparing outlook to proton for my uni classes:
https://drive.proton.me/urls/QSP5CHQ6W8#2thCbXHo29Sz
When Expanded:
https://drive.proton.me/urls/EPMT1Q2438#8b1DnlZUGpdy