For me, the key to keeping it stress free is keeping it simple and not fretting if that means you don't have a zillion sides or if you have to buy items pre prepared.
We have:
Turkey...... prepared crown rather than a whole bird, easier to cook and carve. Cook that Christmas Day then take it out, double wrap in tin foil to keep warm and oven is free for veg.
Roast potatoes, carrots and parsnips. You can peel these the evening before and keep in pans of water on the hob, or prep and freeze. I keep parsnips and carrots in big pieces so they get prepped and cooked all together with the roast potatoes to make life easier.
Red cabbage I make weeks ahead and freeze in tupperware then just microwave on the day. Or if I fancy something different I buy pre prepared carrot and swede mash as it's nicer than I could make and just microwave that. I don't do both to keep it easier.
Stuffing balls/pigs in blankets prep ahead, freeze and cook straight from frozen or just buy ready made and whack in oven.
Sprouts a quick steam on hob.
Gravy I buy ready made and just microwave.
Cranberry sauce out of a jar.
I save cauliflower cheese/yorkshires/other meats for other roasts throughout the year and nobodies' Christmas is ruined because of it.