I am so interested in the concept. I think it may be missing here a bit altogether, and that it may not just be a matter of a missing word.
A beautiful, old-fashioned English tea might have been like this if it had been with family, and it would have taken someone's care to prepare it, but it also could have had an element of formality and possibly duty about it - so not always the same thing.
Old fashioned, family Sunday lunch might have had some elements once, but often the mother was too frazzled and the next day Monday was looming for work and school so it could feel like a depressing count-down, so I don't think that quite got it.
Grabbing and scoffing at a big bowl of greasy roast potatoes with a lot of people crammed on a sofa while watching the television - as in a repulsive (imo) UK advertisement - is more about a nothing-matters-at-all, no mindlfulness whatsoever, cram-it-all-in, binge culture. So that's obviously not it, even if doing that with family and friends would be cosy and comforting and physically filling.
What people hope for out if Christmas here, and sometimes find with family and friends, and all the beauty, warmth and sparkling lights might sometimes be the same perhaps.
What do you Scandinavians find the most Hygge in the UK culture?
(I understand that individual instances could be anywhare, and that within your lives you would create it wherever you go.)