I used to work the Sunday roast section in a restaurant. This is what we'd have done by Friday - complete one job at a time for efficiency. For Friday sub Christmas Eve or even 23rd:
Peel all veg
Cut all veg and trim and halve sprouts
Par boil and shake up potatoes
Par boil carrots and parsnips
Braise cabbage
Start stock for gravy (using veg peelings and turkey wings + backbone if spatchcocking)
Spatchock and salt the bird - if you're a confident Cook generally but just struggle with the full roast, and if you have a full turkey, then spatchcocking is a nice way to achieve a better (less dry!!) cook and get the turkey taking up less height in the oven
Make your garlic butter if you're planning on shoving this under the turkey skin
For Xmas I'd also add prepping the stuffing and pigs in blankets plus any baking/dessert and soup or whatever you're planning
Once the stock is done, you can strain and reduce for a jus, or make a roux with e.g. turkey juices and flour and add some sherry or white wine and the stock in, day before is fine. Honestly though a nice shop bought would be lovely and way less hassle.
This leaves the following for d day:
Put butter under turkey skin (if applicable)
Roast it! Rest it
Then one hour before dinner work through jobs in the following order:
Heat up fat for potatoes in the oven tray and then roast them on 200 - the potatoes should sizzle when they hit the fat
Sprinkle roots with oil, honey and salt and get them in the oven when the potatoes have been in for 30 mins (30 mins to service)
Get your stuffing balls and pigs in blankets in at the same time
Oil and salt on the broccoli and sprouts, get them in when the roots have been in for 10 (20 mins to service)
Heat up your gravy and carve your turkey, I would favour carving into parts rather than slices which would give you at least 8 portions!
Serve!!
YouTube is your friend! Courage!!!