Do what works for you without guilt.
The Elf was never going to work for me. Far too stressful to remember to mess around with that every night. That "tradition" emerged around the time mine were young about 10 years ago. Each year the SM posts about what the elves got up to became more and more jaded as the novelty wore off. I totally made the right decision on that. Neither of mine mentioned it until DS2 was about 9 or 10, and it turns out that he thinks they're a bit freaky anyway.
I do buy pjs and a picture book for a couple of reasons. DH's culture was to exchange gifts on Christmas Eve so it's a nod to that. The DCs need pjs at some point anyway, and 24th December is as good a time as any. The picture book was from when we did bedtime reading. They're teens now. Older one doesn't want pjs, so he can have another present early. I've bought a book for younger teen because I found one that should make him laugh.
I'm not filling a box with other stuff just-because. If that works for other people, that's fine. My two are just quite particular on what they like, and I'm not generating waste on the appearence of abundance that won't be appreciated and used.
We set the hearth up with the mince pies and beverage like I did as a child. For years they were intrigued by the giant bite out of the carrot 
It turned out that DS2 stopped believing in Santa at about 5-6 and kept quiet for a long time. The most "magical" thing for him was how we got the stockings in his room without him noticing. That was a challenge the year DS1 couldn't sleep until 1am and DS2 woke at 4am!
In recent years we've developed a tradition of going to McDonalds in memory of a family member who had a secret love of the gerkins in their burgers. We twigged that they were very insistant that the DCs really did want to go to McDonalds, and this was a front for the moment that they'd sigh happily at the first bite into the burger and comment on the pickles. It's a significant date, and it's this kind of family tradition that has genuine meaning.
You can't do everything, so do what is managable and meaningful.