re: Just booked 22 days to Italy/Greece - any and all advice/tips appreciated

I second the idea to skip Venice and subtract a day from Milan. You can add those days to Florence and maybe a day trip or two in wine country between Florence and Rome. Hitting every major city sounds good when planning, but travel ends up eating a ton of your time. Also, really getting to know a city over the course of 4 days is much more enjoyable to me than popping in for a day or two.

I would also suggest cutting a couple days off of Mykonos. I loved my trip there, but 5 days is a long time unless you are really big into late night parties. 5 days in Santorini is perfect. Please don't take those days off Mykonos and put them in Athens as 1 day is more than enough.