If anyone attending has any of those food warmer / server appliances like @GettingStuffed has linked ask them to bring them. Pretty sure they were on sale in b&m/ lidl/ aldi one year. I swear by mine - I host between 12 and 16 some Christmases and have 2 after seeing them at one of the shops mentioned the other year and it is a lifesaver. Everyone serves themselves, you don't have to worry about who wants what and who can't have certain things touching.
Potatoes half done and then finished off in hot fat/ oil will be fine. Soft veg will be fine in slow cooker or if mainly cooked then bunged in oven wrapped in tin foil for 10 mins or so. Pigs in blankets in air fryer. Boiled veg blasted in microwave to warm up then bunged in food warmer with a bit of water in the bottom. Gravy done in advance and then reheated once there. Make sure it is really hot. If you are tight on hob space what about camping stove or plug in hot plate.
Prep as much as you can. Logistics wise if you can get trays that fit side by side longways in the oven you can get more in. Make the most of as many appliances as you can - slow cookers, air fryer, microwave. If anyone attending has these ask them to bring them too.
Make sure all your serving dishes are hot before putting food in them. Same with hot plates - put them in the microwave/ washing up bowl of hot water or ask if anyone has a plate warmer - I got mine from Lakeland in the sale one year and it is amazing. Anyone who wants lava food can bung it in the microwave and blast it to lava temperatures.
Make sure the table is well and truly taken care of so all condiments, cutlery, drink glasses ECT all set out. I do pour your own drinks set up at the end of the kitchen unit but away from the food server. If there is space on the sideboard in the dining room I do it on the sideboard. That way you have 2 queues one for food and one for drinks.
Don't martyr yourself. Most guests are more than capable of putting their own food on their plate and pouring their own drinks. They are also usually capable of using a microwave if they want food the temperature of the centre of the earth.