Some calendar apps on Android (Etar) offer the possibility to increase the maximium number of lines shown per event. In the monthly view this feature helps to distinguish between similar events.
In the current implementation of the Proton Calendar Android app the event title is truncated after a few characters making it difficult to distinguish between events.

Here are some examples:
"John appointment dentist"
"John visiting Jeff"
get truncated to
"John appoi"
"John visitin"
or something close to that. In the monthly view it quickly becomes tiresome to tap on every day just to understand what John is up to that day - it kind of feels like the opposite of overview. I would suggest to implement an option to show at least two lines of event titles.