Dreamon, I am in north Italy at the moment and while I haven’t packed for a winter trip, I did take my Kathmandu brand down jacket, and raincoat. The down jacket is not waterproof, so I always carry the rain jacket with me.
It was wet and cold last week, and I did stay warm, but damp. Condensation, I guess, I found this article
https://mountaintrails.ie/waterproof...ot-waterproof/

My down does compress into its’ own pocket, so is pretty compact.

My concerns are about pants. I wore my Kathmandu water repellant pants, but they do get wet. I saw people in jeans! Yikes, heavy, and cold, and slow to dry, last thing I would wear. I had leggings on under my pants, so was warm, but did then get hot. Haven’t tried the silk leggings, they might be worth investing in.