The setup is a large weight lifting room. All they want is some loud music, don't care about 5.2, 7.2 etc. but want bells and whistles such as Bluetooth, Airplay2, etc. Stereo is all that is needed, but need to push stereo through two sets of large Kenwood speakers. There are good prices on Denon AVR-S750H (2019) right now. Can I put two speakers on L/R front and put two more on back surround and reassign as a full power L/R set without frying the receiver? I can't seem to find any specific talk and the manuals seem vague about it. Here's a look at the back panel. The rear surround sound speark jackers say "assignable"
https://assets.denon.com/assets/images/productimages/AVRS750H/D_S750_gallery_3_na.jpg
https://assets.denon.com/assets/images/productimages/AVRS750H/D_S750_gallery_3_na.jpg