I’m from the tropics. There was one day this winter where I had to dig out jeans and a cotton long sleeve t-shirt for a couple of hours in the morning when it was “crisp”. So that’s the extent of my cold weather dressing skills
lol that's "summer but raining" UK clothes.
More of those tops for layers.
Add a vest underneath if needed, so buy a few of those.
You'll need a chunky cable knit jumper on top or a polo neck. If you're just holidaying for a week you can get by with one or two because you're wearing layers underneath it anyway so it won't be getting dirty unless you drop food on it or something.
A short padded puffer jacket or long wool coat, I have both in my winter wardrobe.
A huge scarf that can double as a small thin blanket if you unfold it, for putting over your legs when you're sitting inside without your coat on.
Gloves, bobble hat/beanie hat and an umbrella. The latter because truly waterproof coats tend to be ugly AF and I care about such things. A hiking type coat with a hood, if you aren't so bothered by aesthetics or if you're actually going to be hiking.
Jeans are fine but more than one pair in case it rains and they get wet or get splashed from a puddle. If they're wide at the bottom turn up the bottom part a few times/inches when you go outside so they don't soak up wet from the ground and let them down again inside to keep your ankles cozy when your boots are off. My jeans trail on the floor when I'm not wearing shoes and that's how I like them.
If you're going to be standing around outdoors for hours you might want to buy jeans in a bigger size and wear leggings underneath them so buy a few pairs. If you're walking you should be fine in just jeans because the exercise helps you stay warm.
Regular skinny socks with thick chunky socks layered on top. With some percentage wool for the thick ones is warmest.
Boots, leather or plastic, with some fleece or a bit of padding inside will be warmer. Ensure they fit over your double socks, you might need to go up half a size.