Damn, no honest explanation forthcoming.
Even though I do think you are being very mean-spirited to not want to drive a 30 minute round journey on Christmas evening, I also think that you need to stop martyring yourself on Christmas Day - you really need to put your foot down over this!
For many years I was the one who thought about, ordered, shopped, prepared and cooked the Christmas Dinner. I was also the present getter, but my DH at least shared the wrapping with me.
I never did the washing-up. Washing-up was shared between what adults were there, ie my husband, my parents, and my MiL, I left it up to them to sort out who was doing what. If anyone wanted sandwiches later I would make them as well (my DH might have helped with buttering the bread if he hadn't also fallen asleep in a chair! My husband was the main drink provider and server.
I would rest between the end of Christmas dinner and the sandwich supper, which was usually about 5 to 6 hours, depending on everyone elses hunger levels. My rest may have included me watching TV with the rest of the family (or the DC playing with their toys - depending how young they were), and us all playing board games, or later on in the day doing a quiz. But nearly every Christmas Day included me going upstairs for a nap, while DH watched/played with the children, and the Grandparents fell asleep in front of the TV!
OP you really must should insist that you get some free time after "the" Lunch, to do what you need and want to do for yourself - whether that be having a nap, having a long soak in the bath (if you have a seperate loo), or going for a nice brisk walk, or even a slow meander 😉. If the others refuse to help then please just refuse to host anyone but your own young children. It would probably be quite helpful for you if you have this commitment from the adults promised before the big Day itself...