I am from the US South, and I grew up in an older home without air conditioning. Because it was built before AC, it has high ceilings, transoms, and large shaded porches. Still, it got hot in the summer, so we slept with only sheets and used fans.
Wherever I travel in European countries, I notice the lack of top sheets. There’s a bottom sheet and a duvet, but there’s nothing thin to drape over your body.
I know heat waves happen yearly now, and with global warming are likely the new norm. So do you sleep with nothing on top? Or are you rethinking top sheets? They really are great when it’s hot but you still want to feel cozy.