I am familiar with much of the equipment you are talking about. My first reaction is that most likely it is something other than the integrated. each piece of gear checks the box… that’s good.
It would be helpful if you could post photos of your system. There is a place to create your virtual systems.
To answer your question directly… the Boulder or Pass amps would be great choices that will give you greater punch and accuracy. I don’t recommend the Luxman… to me they are too trebly and midrange / bass shy. I do not have experience with Accuphase, but I am pretty sure it would be in the running with the Boulder and Pass.
Each of these three integrateds have the advantage of being significant upgrades over what you have today… all be it all solid state… so they are going to be more accurate sounding.