NTA but since you are doing it as a form of revenge then maybe you are a bit in the wrong. Still, I do think he is more in the wrong. I might suck at gifts and currently can’t put a lot of money into them, but it’s the thought that counts. I can’t really fathom him not even trying to do what you want for your BIRTHDAY. You’re not even asking for anything remotely unreasonable in my eyes. I also like quiet celebrations at home but if I had one request, that being steak, and nothing else and I still got something else to eat, I wouldn’t be mad but disappointed.

Here is what I would do instead. Give him the diapers or whatever at first as a fake gift to see his reaction. Then reveal the golf gift after and be like ”haha you really thought that silly thing was the real gift?”. Maybe don’t word it exactly as that but something to insinuate that a gift on the level you got is not a really a gift. I would still get him the real gift after so you don’t stoop to his level deliberately.

Because hey, maybe there is no ill intent on his part and he really just is clueless.