Advice on DSP streamer

I'm trying to sort out the best path to take to incorporate DSP room correction.  Room is 15x12x8 with two open doorways.  I have two tube traps, two acoustic panels behind the speakers, other physical tweeks to the room, and equipment  isolation (Isoacoustic pucks and Vibrapods).  System is Cambridge CXA81, Bluesound Node 2i, Wharfedale Jade 3 standmounters and an SVS sub.  I believe I've taken the physical room correction as far as I can, given already generous WAF.  Remaining issues involve a little muddiness around the 300-500hz region that shows up mainly with paino music.  Always looking for better imaging.  Hence DSP.  Tentative options are: 1) replace the Node 2i with a miniDSP SHD,  2) replace the Node 2i and the CXA81 with an NAD M10, 3) replace the Node 2i with an NAD C638 (and keep the CXA81 as a power amp),  4) replace the Node 2i and the CXA81 with an NAD 638 plus an unspecified (used) power amp.  There are, of course, more expensive options such as Linn, Trinnov and Lyngdorf.

I should note that I like the "British sound" and am otherwise quite pleased with the CXA81 and the Node 2i - but I am having trouble figuring out how to best incorporate DSP.  Source is mainly Qobuz.  I realize that Roon is an option but, frankly, its room correction feature confuses the hell out of me. 

Thanks in advance for your comments.