We are not seeing them until NY really.
I will visit a DAunt who lives near us for a drink/catchup on Christmas Day for an hour. And a different DAunt on 27th or so.
Otherwise, it will be our household, neighbours, friends etc until we make the trek. There's a gathering for NYE in DPs holiday house, so that involves 1 DSibling and DSpouse, and DPs. We will call to DH's DSibling locally to there en route, with DSpouse and 2 DCs. DMIL may be visiting there.
We will also have to make the further trek onwards to where we both grew up, to see DMIL and other DSIblingIL, DSpouse and 3 DCs.
1 more DSibling mentioned calling to us as they go past to the airport.
I met 1 DSibling, DSpouse and DC at an event earlier this week and had lunch with them afterwards. And 2 others live abroad with their DSpouse/DPartners and DCs (4 between them).
It was frankly a miracle that we all saw each other in person this year, as we hadn't managed that in a few years. But there was a weekend where we were all home in the family home for an event. (Not all the DSpouses and DCs managed to get there - but there are significant distances and time zones involved).
I am looking forward to unwinding this year as it has been far too busy a year.
The years that our household travels "down home" for Christmas (and yes, it is still expected), we rent a cottage nearby as we are pulled in 2 directions between our 2 childhood homes and there is serious grief in both about spending too much time in the other and never actually getting any time just on our own (we always need some downtime of our own as the lead up is so manic - but we blame DD now, and she happily concurs, that with her ASD she needs some quiet space).
I am still the black sheep of the family for teenage misdemeanors, despite being a totally totally different person now. So I don't voluntarily go into the hornets' nest without a game plan, retreat tactics, and camouflage in place.
If your DM really wants you to visit, but has already filled the rooms, then she would have to accept that you NEED to stay in a hotel locally to do that. Would it work to just point out that obvious logic?
(I know - you probably already have, forget I even mentioned it.....)