Christmas eve is antipasti #1. Lots of meats, olives, artichokes, cheeses, salad, etc. If DP can work out a good GF recipe for chilli cheese straws, they'll be made and after eating several tonnes in front of the TV, the rest will go into a tub for picking at. I used to do a fish meal, something like salmon or cod, peas, potatoes and a fuckton of Dill, but DP isn't a fan.
Christmas day, small cooked breakfast in the morning (something like egg and black pudding), then dinner sometime in the late afternoon or evening, as it's just a Sunday dinner with more veg, possibly something like fruit in the evening (if we can fit anything else in, which is unlikely as Christmas Dinner inherently contains at least 2 types of potato in ridiculous quantities and around 5 separate types of veg with assorted condiments and sauces).
Boxing day, second small cooked breakfast and using up meaty leftovers for a prolonged antipasti#2 in the evening with lots of fresh salad items, pickles, grapes and probably crisps.
By Day 3, we're most likely swapping breakfast for some sort of brunch, maybe avocado GF toast and bacon, eggs florentine, boiled eggs and asparagus or egg, ham and cheese and the evening meal is likely to be a curry (normally 2 vegetable side dishes, one pulse based, plain rice and possibly a few onion pakora).
Then normal service is resumed until New Year's Day when it's usually gammon (because DP loves the stuff whereas I'm happy to cook it but also rather meh about eating more than a couple of slices). I'll knock up some pease pudding and then any leftover meat will be sliced up and frozen for him to enjoy over January.
The treat side is that the cost isn't relevant; fancy the posh melon instead of a sweaty looking tub reduced to clear on Christmas Eve? Add it to the order. Fresh strawberries and coconut yoghurt? Fine.
I don't do deprivation. I do enjoyment, and where Christmas is concerned, that means days of lovely food and getting as much daylight as possible, not holing up and feeling obliged to have tens of thousands of calories of stuff that isn't as nice (in my opinion) because it's been marketed to be a 'treat'. Which for us means eating as much of what we want only if we want it/are hungry, rather than forcing in another meal out of obligation.