I think there could be a middle way than moving into a smaller place immediately and effectively abandoning the family next Christmas! This won't work at all, as they will have no clue why you did this and your relationship will deteriorate. It is also too long term and your resentment will build. You need to do something now to let them know how upset you are, but also perhaps reset the relationships on many levels.
None of this sounds unfixable to me. They spent a lot of time in their rooms, were stroppy when asked to do chores and called you some unpleasant names. These all sound typical of teenage behaviour, but also typical of things that you have to absolutely clamp down on, or the name calling in particular. But nothing out of the ordinary on the teen boards at least, I don't think.
The Christmas dinner situation was very difficult- their dad called so effectively they were pulled in two directions at that time, with you fuming downstairs, and him being Disney Dad upstairs. You have incorrectly read their choice- they are sure of your love and unsure of his as he is flaky and crap, so they chose him because of that, not because they love you less. I think cutting a bit of slack around the timing of dinner would have been ok for you here.
The balance of power in the house is wrong, and there are no sanctions for swearing at their mum! I would decide what your bottom-line issue is here, and for me it is open rudeness and disrespect. I would be less fussed about them all being in their rooms for a few days, they need to relax, want to be together, and had you been busy with friends/your own family/activities, this wouldn't have felt that bad. My dd (12) is practically living in her room at present, though she comes down for food and the odd visit to relatives if we make her. I don't see this as a reflection on me, it's her down time.
But the swearing/name calling/nastiness has to stop. So, what is the consequence? I would have a simple- one name- one day of the internet off or whatever. Or ask the eldest to leave the house if he is going to be rude to you.
There are no consequences, they get to eat everything, do what they like- this power balance of you being essentially in charge has to be restored. But equally, I do think you need to back off a bit with the guilt over not spending time together, they did spend time with you and their behaviour is pretty usual for a lot of teens.
I would also divide and conquer. They are three, you are one, take them out individually for a coffee or make time for a chat and tell them how upset you were with them swearing at you and say that you won't be tolerating it in the future and what the consequence will be (no lifts to activities, no cooking that week or whatever).
If they were nasty to you daily, I would call it abuse, but I'm betting a lot of teens have stuffed up by saying bad stuff to their parents in the past- it's what you do about it that matters.
I think making a life for yourself is an excellent idea anyway as they are growing up a lot and very independent, and also get on well which is great, so your individual relationships with them might be less 'all round the Christmas tree singing carols' and more about individual time spent with each one, in amongst seeing your own friends etc.