algorithmic complexity is 100% absolutely orthogonal to the stuff you've mentioned

what you're describing is something different than big-o, in the sense that is commonly understood, and what your interviewer almost certainly intended

I understand what you're describing and talking about but it's not big-o

I would guess that you haven't had any kind of formal cs education? no shade but like there are some important topics covered in those curriculums

I have. I understand big-o, I understand that it’s just algorithmic complexity. I understand big-o is not a performance scaling model, because algorithms run on real hardware. That's fine. Some people enjoy petting spherical cows, and some people work with the nuances of reality. That's also fine.