IF you have a display that can it roughly a 1000 nits, then for movies and games yes definitely the difference with SDR is pretty huge.
If you have say a 400 nits display the HDR may actually look worse than SDR. So it really depends on your screen.
If you have say a 400 nits display the HDR may actually look worse than SDR. So it really depends on your screen.
Given that monitors report information about their HDR minimum and maximum panel brightness capabilities to the machine they are connected to, any competently-built HDR renderer (whether that be for games or movies or whatever) will be able to take that information and adjust the picture appropriately.