Dear god, why do people here to be so fucking horrible? Some of us have a sense of 'family' and a duty to spend Christmas with them, because, well, it's for families? It's not that easy to tell your closest family members to fuck off and not come! I'm gathering that they invited themselves?
Also it doesn't require that much intelligence to surmise that OP and her DH hosted multiple Christmases prior to Covid...
Flights will be booked by now, so it would probably cause major upheaval to refuse to host this year. However, I'd reply that you will be unable to host a Christmas dinner if they can't babysit and do some basic prep for you on Christmas Eve. Tell they you are just as tired as they are, and you're looking forward to a break.
If they refuse to help, then don't do a Christmas dinner at all. They can have oven chips and frozen sausages. I do hope they are paying their way, and not expecting you to pick up the entire tab?
I hosted one Christmas and the family members (who I love dearly!) sat there and watched me to it all, and that was the first and last!
Do not be taxi either! If they won't be generous with their time, then neither should you.