No - you are not being unreasonable. Everyone's situation is different and the last thing anyone needs is to feel anxious or guilty about Christmas spending! That's not what it's about.
I decide what we can (comfortably) afford overall, then break it down into how much we'll spend on each, being as fair as we can.
I do the same for birthday spending throughout the year.
We give our 9 grandchildren presents or vouchers, depending on their age and what they're into (no more than about £35 each but do help out at other times where we can)
For their parents (my kids and spouses) - we save up our Tesco vouchers and triple them up on restaurant vouchers for them to enjoy a meal out on their own or with the kids (babysitting can be included). £20 Tesco vouchers gets a £60 restaurant voucher.
My DH's 2 adult daughters with no partners or kids - we give smallish presents.( about £30)
Our siblings, their spouses and the "children" (our nieces and nephews who are all grown up) - we don't give anything now by mutual agreement.
All our children, their spouses and the grandchildren get individual birthday presents.( again usually no more than about £30 unless it's a special birthday)
There are various websites where you can get discounts or cashback which can make the available funds go further. My husband uses one tied to his previous employment in the police. I use Complete Savings - you have to buy something every month to get the £15 "bonus" which then "cancels out" the £15 monthly fee, but I've found it has saved me a fair bit of money overall. Both of the ones we use give around 4% off if you buy supermarket top-up gift cards and more on some items. We use them all the time for our Tesco/Asda/Wilko/B&Q shopping and for vouchers for the GC. If you spend £4000 a year across a range of these, that's a saving of around £160 by doing it that way.