Day-to-day planning was maybe not the correct wording from my side. What I mean is the following: I enter all the races I plan during a year in my *Garmin* Calendar. In my *Google* Calendar, I plan for example when I have holiday from work, or when my kid is with me or not (I'm co-parenting), so I know on what day I can race.
Being able to see the full Garmin Calendar in Google Calendar would for example allow me to plan for the summer-races already in January. Now I always have to open up both Google Calendar and Garmin Connect Calendar to see both full calendars and be able to do this kind of planning.