That's what I did before, I don't have faith on multi channel AVR or amplifiers, never even occur to me not to use a dedicated power amp for the front two channels. Even the center. I just used the AVR internal amps for the rear two speakers.
Own designed power amp, own designed preamp, JM LAB Focal Alto Utopia and Spectral 913.1 speakers, Rythmik F12SE sub.
Not hooked up: Nakamichi Stasis PA-7 power amp, Velodyne VA1210 sub, Kef Reference Series center, Kef Bookshelf speaker, Monitor Audio bookshelf speaker, Infinity rear speakers. Acurus 3X200W amp.