I'm an atheist raised by atheists. We did all the non-religious Xmas stuff. Tree, presents, big meal, etc. Our tree didn't have a star or an angel on top. We didn't go to mass or have a manger scene. I honestly didn't even know about that aspect of Christmas until I was an older kid and saw what friends had at their place.
I know Jewish people who do Xmas just because it's so much a part of the American culture and they grew up being basically forced to participate in school and with their non-Jewish friends.
Now as a singleton with no kids and no family nearby I usually do nothing or get Chinese food with the other non-participants. I used to work, to cover for the people that do participate, but my current job just closes for the week between Xmas and New Years so I'm off regardless.
The early Puritan settlers banned Christmas. Fun to mention that when people talk about what the "founding fathers" wanted.
https://theweek.com/articles/479313/when-americans-banned-christmas