The new amplifiers is getting warmer and hot

Well they did have quadraphonic in the 70's
Have no idea what receiver or preamp was used
All I know is it didn't last long

Because the cpu for the video processor runs 100% unless you have it on economy mode. Most of the excess heat comes from the video processor. There will be a small patch on the top of the chassis that is much warmer, hot even, if you’re watching a long movie. That is precisely where the CPU is. I had this problem with my Denon X3400H a few years ago.

Expect the amp to get very hot by the end of a few hour long movie, and expect critical failure of many of these Denon amps (heavily used ones) from the mid-late 2010s to start failing in a few years.