I think it’s absolutely fine!
They are your children you can buy as much as you want for them. Thinking back to when my DCs were 6 & 4 they got way more than that, that year. I know I go mad each year, but as their parent I can buy as much as I bloody want.
Rough idea of this years,
10yo x 30+ gifts including main present (sewing machine) accessories, learning to sew books, threads, bobbins, material etc…, clothes (Nike pro leggings etc) PJs, other wanted gifts, drawing/colouring books, soft toys, switch games…
8yo x 30+ again, main present (drawing table) and lots of art & drawing accessories to go with it, more Nike leggings, T-shirts, coat, other clothes, pjs, makeup and so on.
5yo x 20+ slightly less but her main present is huge (Barbie dolls house) her presents are bigger in general so will probably actually look more next to her sisters. The lower number is mainly related to all the clothes the older 2 have got, youngest dosnt need more clothes, especially not branded ones and that she dosnt need as many accessories to go with her main present as she has plenty to go in the house.
I haven’t done selection boxs and Christmas chocolates yet but I usually fill their stocking up with chocolate Santa's, kinder choc, coins etc, I also wrap bigger selection boxs, meter long Oreo’s or other things like that.
In the past it has all gone under the tree and we’ve never specifically said either from Santa or us, last year they became more aware of us buying presents, this year we will clearly label what’s from us and Santa, main present and anything related will be from Santa everything else from us.