So, the API to the rescue! I checked the documentation and noticed there is an endpoint to create a filter on a table view. You just need to pass the id of the view in the url and set the field, filter type and value in the body.
It looks like filters are already working in the backend via API, and only the UI in the frontend to add filters and/or react to filter changes is missing
It would be super useful to be able to filter the calendar view from the user interface.
From what I understand, it should be pretty easy to implement, since 1: filtering the calendar view is already working in the backend, and 2: the filtering works perfectly with the UI on other views.