Had a chance this afternoon to do some testing. I watched The Tomorrow War on Amazon Prime, the scene where Chris Pratt is exiting the Lab down the stairwell and goes into the street where the fighter jets are bombing the aliens
I was listening at -25db which is loud enough for me, with Dynamic EQ and Dynamic Volume off. I alternated between Reference and Flat watching the whole scene in each mode multiple times and couldn't really detect much difference, but having said that I do have a slight preference for Reference mode. Sub level of -8db in the AVR is plenty enough for me.
I am now really pleased with the results