I think there are lots of perfectly fine ways to “do” Christmas and it can be a lovely, enjoyable time without feeling “the spirit” or magic. I try and protect the bits that my family like best, and go from there.
Dh likes to be able to relax, snooze by the fire and not have anywhere he HAS to be for the few days he has off, so I schedule busier days with the dc after. He would rather poke himself in the eye than visit Santa or endure a panto, but he’s much better than I am at taking them skating, or skiing or to anything loud.
I leave him to do anything he’s interested in (he’ll cook Christmas breakfast for instance) and I’ll do anything that I love and he gets stressed by (wrapping, Christmas trees, lights), we ditch the things that don’t matter, and we split the rest, as fairly as possible.
Contributing is really important part of ownership, belonging and valuing experiences. Don't be afraid to ask for help - it isn’t good for anyone’s MH to be passive.
I know which Christmas foods he likes best so I prioritise those, and avoid making them any other time of the year - they are literally the taste of Christmas for him.
I know some of the things that make Christmas difficult and either avoid those or make an effort, eg we both make an effort not to fan the flames of our respective family’s dramas. There’s a lot of obligation/guilt with his family, that gets heightened this time of year. I’ve found that letting him get on with what he feels he needs to do and not creating counter demands on his time and attention has, counterintuitively, helped him prioritise our little family.
He doesn’t mind Christmassy stuff in small doses (like driving to see the lights, or walking through a Christmas market) but I take other friends and family to Christmas fairs, ballet, carols etc. He’s happy to stay home with the dc because he doesn’t have to go.
When the dc were small and intimidated at the idea of walking in on Santa Claus, they used to get him to check first, and that evolved into a ceremonial role. No one goes down on Christmas morning until dh has declared “he’s gone” - letting incidentals like that become traditions is kind of magical but it’s also easy to miss them if you’re not looking for them.
Advent calendars have been fun, because the dc take a huge interest in who got what. I was cynical at first but they’ve been a lovely way to count down to Christmas. On the years when dh was the only one with chocolate, he’d end up sharing it with the dc.
I agree with other posters about giving in some way. There’s a cause very close to DH’s heart, and I keep an eye out for festive events relating to it. One of the dc gifts to him is always a donation to a particular charity. And there’s a sad backstory to that, so incorporating it into Christmas rather than making it something to avoid thinking about, helps a bit.
I can’t imagine him ever finding it magical per se but I think he enjoys our family Christmas.