This was a brevet I did in May. Getting to and from the lakes was a bit of a chore but the route around the lakes was stunning. Great climb away from lake Como with views across to Bellagio.
I rented a bike in Milan but there are a few places in Como itself. Get some local knowledge.
https://www.openrunner.com/r/4503519
https://www.uslegnanese.it/randonnee/