So some context. Ive been working on my homebrew capmpaign that I originally made back in collage(10 yrs ago) and ive finally been able to be the DM of my group. Two ive played with for a good few years now (N and A respectfully) while the other three include my S.O and two newbies (H, F, and M).

So I'm having issues with A. He is a power player through and through. Builds his characters min maxed, and tries to be the power house as well as the one with the most knowledge. (Rock gnome artificer battle Smith) and he plays his character the way his character is. Thats not the issue. What bugs me is that he doesnt seem to be having fun when I dont give him information he asks for when he does his intelligence and skill checks. Im trying to not be meta gamie with his rolls by giving him information that no one knows since everything hes asking for has to do with an unknown, hidden language. I'm using the actual idea that it takes years of deciphering to reveal and translate a new language.

Im not sure if its him being pushy, or am I actually doing a bad job. Any advice?

Edit: he also argues with me on a lot calls that i make.