IOM cost ten less than your Tube Amp because IOM amp is assembled from bought parts, not made from the scratch.
And because High end tube amps are hype
and are a small market for healthy customers. You pay for the name, not for the product. That's a common fact.
You probably don't listen to IOM amp before buying it, it's a common mistake, I made it too with Topping dx7pro.
I moved from a Class D Abletec amp to ncore amp, the gain was a small improvement in umph and less distortion at high volume, sound was nearly the same.
So Ncore is not the problem. You don't like it's sound, fine, sell it and move on