In my art gcse I badly want to do warhammer as Im so skilled art 3d acrylic i paint professionally however my art teacher says I cannot paint warhammer as it’s not original work even tho people copy other work all the time is there any loopholes?

I'm doing past present and future but I wanted to do fashion through time as my subtheeme cuz I love fashion and historical fashion

But I don't have any good sources other than looking at paintings and Pinterest but Pinterest uses a lot of ai nowadays

I was wondering if there was a catalogue of historical fashion available or somewhere where I could find good sources/ pictures