I agree with
Puzzle books
Age appropriate colouring books & some nice new colouring pens pencils
There are simpler versions of Rubik's cube type puzzles this kind of thing:
https://www.amazon.co.uk/SEWORLD-Twist-Popular-Transformable-Puzzle/dp/B078SH91LG/ref=mpssa1112?dchild=1&keywords=brain+teaser+puzzles+for+kids&qid=1604126388&sprefix=brain+teaser+puzzles+&sr=8-12
My siblings and I used to love that sort of thing around his age as did dd
Go even more retro with this kind of thing which seems to be having a resurgence in popularity?
https://www.amazon.co.uk/Ninja-Sliding-Puzzles-Pack-4/dp/B07QGFM7M6/ref=mpssa1117?dchild=1&keywords=sliding+puzzles+for+kids&qid=1604126546&sprefix=sliding+&sr=8-17
This sort of thing is weirdly addictive and actually quite challenging
https://www.amazon.co.uk/Childlike-Water-Machine-Handheld-Colors-Random/dp/B07ZRQSVPC/ref=mpssa112?dchild=1&keywords=handheld+water+puzzles+for+kids&qid=1604126623&sr=8-2
There are harder versions for older kids
or whole packet of Tunnocks Tea Cakes....
Wish someone would get ME that! 
I was a bookworm so in mine there'd usually be a new Enid Blyton Novel (bro would get some kind of 101 things you never knew about... book and sis would get roald Dahl book - so depends on his reading preference) inc a new bookmark, a satsuma, choc coins, carton of 5 alive, word search puzzle book and new pack of highlighter pens for that (much better than ballpoint pen)
Around this age I started getting dd annuals which are still around but you have to hunt to find good ones as they're not really a thing now.
Came about from a discussion like this about what I used to get in my stocking as a kid and I mentioned I often got a blue jeans or Jackie annual, she knew about the magazines - but she was like
"What's an annual?" 
And then I looked in usual shops and they weren't there, had to go to a traditional book shop in the end and she loved them! I think book retailers are missing a trick there!
You can get crap ones easily enough online but to get ones like we used to have you need to hunt a bit.
I'm with you, I raised dd alone and I did not need waking at 4/5 am and then having a full on day with her hyped up and no respite!
As well as enabling a little more adult sleep this takes the edge off the hype for them and they're a little bit calmer and less given to getting fractious which is no fun for them either.
I think the trap you've fallen into thread wise is that people do their Christmas their way and find it very strange if others do things differently.
First Xmas I spent with another family totally threw me! Not least because they didn't open presents until tea time! Not even the little kids!