Unless you are using Multi-Channel Stereo mode, you probably don't need to use external amps, especially not for Surround and Atmos ceiling speakers (which are usually small speakers rated for 10 W - 100 Watts of power).
If the higher master volume knob setting is disconcerting to you (I know you're losing sleep

),you can increase all the Speaker Channel Levels manually by +3dB or +6dB. For example, if your Front Left Speaker is set to 0.0 before, increase it to +3.0 or +6.0. Now your master volume will not have to be set that high.
You do need to put 2 or 3 fans atop your AVR to pull heat out and keep the AVR operating cooler like this: