I have a proposal for an improvement. When creating events I need to switch calendars very often (several times a day). Some things go to my personal google calendar, some go to the family one shared with my wife, some go to our house renovation scheduling one.
My current setting is that I add the event to the last used calendar.
For switching calendars I have to tap the column with last used calendar, then the list with calendars appears and I choose the one I want to put the new event to. (Screenshot 1)
If it was possible to have buttons for most used/favourited/first four/etc. calendars, it would save me that one inter-click to open the list with available calendars and choosing another one. (Screenshot 2)
Similar solution already works in month overview to turn on/off calendars. (Screenshot 3).

screenshot 1: https://e.pcloud.link/publink/show?code=XZYw9EZHnncMQA0O486C3tvDtPLlLOEd5D7
screenshot 2: https://e.pcloud.link/publink/show?code=XZuw9EZlRpF699JmKk4CubbCjF9OX7fAPh7
screenshot 3: https://e.pcloud.link/publink/show?code=XZ1w9EZG5t3HN06RYyxER3G5D42e056C5kk