Inverted Y works for me in first-person games because I equate the tilt of the stick to tilting my head. If I want to look up, I have to lean my head back.

In 3rd-person platformers, it's because I'm imagining moving the camera. It's also why I have to invert the x-axis on third-person platformers.

3rd-person shooters I just treat as an fps because that's how my brain works.

Yes, the y-axis must be inverted. Otherwise I spend the whole game staring at my feet or the sky.

Oddly, growing up my younger brother was the opposite. It was annoying to take turns playing games with him, because we have to adjust the settings between handoffs.