I highly recommend Isola Comacina. (
https://www.comacina.it/en/restaurant.php)
I would suggest an alternative itinerary. The drive to Bellagio is difficult and the village itself is overrun with tourists and quite small.
There is a fast train from Milano Centrale to Varenna. Varenna is a small place with much less crowds and would make a great place to stay a night with fantastic views of the lake. Then you can get a ferry to Isola Comacina that will give you an hour or two at Bellagio. For me that is more than enough. After all those stairs you will feel like your lunch on the island. After lunch rejoin the ferry to take you to Como stopping along the way at several small townships on the "wealthy" side of the lake. From Como there are trains that will take you back to Milano. Of course you could choose to stay there overnight and there are several nice sites to see around Como. The old centre itself is rather nice.
Enjoy.