The BlueSound Node is the Honda Accord of streamers. Affordable, works and sounds better than most give it credit for, and about as reliable as any piece of hardware gets.
I won’t trash your Marantz because most of the criticisms are either speculative, or simply irrelevant (What difference does 10 dB improvement in dynamic range or noise from 80 to 90 dB make when the noise floor in your room limits dynamic range to maybe 60 dB? I live in a very quiet house, and the noise floor is 42dBA. My System is capable of peak output of about 110 dB, but my usual listening level is around 90. So, 90-42 = 48dB typical, 68 db maximum dynamic range). Your Marantz is a great piece of equipment and while Marantz and Denon are sister brands and do share a lot of parts, a high-end Marantz is a totally different and much more carefully engineered component than their mid-fi offerings. That just doesn’t fit the ego-fi narrative.
Yes, room correction does happen in the digital domain, and most find it a worthwhile option. But even the best room correction, speaker placement, components and cables can only effect the input of the system into your room. It is the output of the room predominates what your hear, and improvements made in that function are almost universally the biggest value to be had in upgrades. Consider some acoustic treatments - sidewalls first, then bass traps, and ceiling. Profound improvements can be made in most listening spaces for under $1000 with packages from companies like Acoustimac. Their options for color and finish also enable a high degree of SAF. Acoustics is applied physics, and applied physics is math, so use their, or other online calculators, to determine your actual requirements.