This year I think I'll be spending about £350 for my DD and just under £300 for her 2 younger brothers.
They're all quite young so I do feel they're still at a stage of genuinely needing new stuff each year. Each has very different tastes too so apart from Lego the younger 2 haven't even really had suitable hand me downs from their siblings.
We also have a very small family circle and only have 1 other relative buying, so I do honestly feel the pressure a bit. It's no shade at all, but sometimes people say they only spend £50 per child at Christmas, but then that child has e.g. 2 sets of grandparents and multiple aunts and uncles buying gifts too.
I will say, I don't set a max budget and try to reach it. I spend ages carefully making a list of things I would like to get them, considering things they have asked for, hobbies and interests etc, and then cost it all out and see what's feasible. I'll assign things to the one family member who kindly buys for my children within their budget, then I'll figure out what I can cut down or replace if needed, and look for deals. If I came significantly under budget I would be really happy, and definitely wouldn't buy more for the sake of it.
The only time I would buy more is if there was a huge disparity between the number of gifts, and then I would focus on consumable stuff like play dough, bath stuff and the like.