I’m a bit down on Innuos currently - I’m sure just due to my system parameters - super impressed with its detail air and space but not with its lack of image stability and solidity in my current system.
When I first got my Innuos Zenith MK3, I had a similar experience. I know someone mentioned the SR Purple fuse earlier and you commented that you wanted to keep the playing field level. However, the SR Purple fuse had such an impact on the sound quality that honestly I was shocked how a mere fuse could do this much. You already gave the advantage to the N20 by playing to its strengths when you tried the AES output. I strongly feel that the Purple fuse is Innuos' key strength. You should at least give it a shot. Plus it's only $200, you can return if it doesn't work for you. In my case, it helped tremendously by providing more stable and vibrant imaging. The increase in soundstage depth and width and the extra vibrancy the fuse provided was not subtle at all.
Secondly, if you are planning to try out dacs within the $7K range, let me be the first to tell you that you will be disappointed. While they might reach the potential of your built-in dac, I seriously doubt you will hear any improvement. A well-designed, well-thought out built-in dac gives the designers several opportunities to fine tune performance which is in line with the overall sound signature they are aiming for. If you're lookin for substantial improvement I strongly feel you have to set your sights on a higher price bracket. Lalitk has the Merging dac which I believe is the real deal. I heard it at his home last year and was very very impressed.
Lastly, I really appreciate the feedback you are sharing with the audiogon community. There are very few people who compare high-end streamers in their own systems and faithfully report their findings without any bias. I certainly have enjoyed reading your posts and find them very valuable. Thank you for sharing!