My room is mid sized and kinda oddball shaped, think I need some significant room correction, especially to fix muddy bass.
I would treat the room before buying anything new, otherwise not much point.
I would recommend a room kit from sonitususa.com. As far as a new processor goes don’t pay for features you won’t use. Maybe an 11 channel atmos/auro 3D channel processor is a better fit than a 16 channel processor like the AVM 90 or 13 channel MX123. Maybe the Mac MX-100 or their new 7.2 channel receiver which can expand to 7.2.4: