I've not read all the previous posts but this is my take on your post .
I completely agree that Christmas has become far too commercialised and children get far too worked up about presents. But there are ways to do your own thing and not be sucked into it all.
1 Your children should be taught the reason for celebrating Christmas (religious) and if they and you are another faith, fair enough, but they still need to understand its origins - which is not Santa Claus and gifts.
2 You need to explain to them that any gifts will be within your budget. They won't get everything on their wish list.
3 You should not feel pressurised into spending more than you can afford. It's not about getting loads of gifts.
As a family we'd be considered 'well off' and now my kids are adults, they too are earning 6-figure salaries. We put a limit of £20-ish per person on Christmas gifts because we refuse to enter in the panic-buying consumerism that it's become.
We treat it as a day of the year when, we hope, we can all get together over lunch. It's not about gifts and never was- even when my kids were young.
Try doing the same and you'll be a lot happier.