Any runners/joggers here? Where to run in Milan, Florence, Bellagio?

Have you looked at the Great Runs website?

https://greatruns.com/location/florence-italy/

I asked a similar question about Florence 4 years ago and here’s a link to the very helpful answers I got:

https://community.ricksteves.com/travel-forum/italy/running-or-biking-park-places-around-florence

I spend a lot of time in Florence. I like running through the city early because the town doesn't "wake up "early" and there is just deliveries going on. I also enjoy running along the river. Another good one is up to Piazzale Michelangelo where you will have wonderful views.