Honestly, I'd suggest a prioritsation matrix here.
Classify all the tasks with an impact / ease score from 0-5. Multiply the numbers together to understand the relative priority of each item.
It won't be perfect but it will a good place to start.
You also do this at a product level instead, and invest all your time onto one product to begin with. This might reduce your switching costs working between projects/products.
Personally I find this kind of approach infantilizing. I don't think it's fair to have an expectation of yourself or of your colleagues to spell out in Google Calendar what you/they are spending their time doing throughout the day. People should look at gaps in people's diaries not as opportunities for new meetings, but as time someone is probably spending doing something important or interesting.