@OP. If you are not interested in two channel audio, I would leave things as is. Congratulations on your room treatment. You are losing some of the benefit of it by having furniture covered in reflective materials and also the very large table between the couches. I'm presuming you move the monitor on the arm out of the way when listening to music.
Moving to separates
Does anyone have an experience they'd like to share about going from just an AVR or integrated to using external amp(s)? My Integra AVR has 100 W per channel (class AB), all channels driven, and sounds very good, so it is not clear to me that there is any advantage to connecting its preouts to a separate amp. Might be a total waste of money. Please mention your specific equipment. Thanks!