So I had the same issue recently from long storage (6 months).You'd think by now Fiat would have come up with some kind of a fix for this. It's annoying and a real design flaw; whoever their engine designers are, they should be embarassed. Chief of engineering should have been fired to release this out into the world. It's this kind of thing that has contributed to Fiat's lousy reputation.
That said, I just take my Lusso out every two-three weeks in winter on dry days and run it up to operating temp and charge hard through the gears a couple of times, then it's good to go for the next time.
Fiat told me to start it at least once a month for at least 15 minutes or drive it around like you mentioned during storage times.
I guess this is how we have to take care of the princess. Always needs our attention 😁