Very glad you are pleased with them.
My experience is that simpler is often better and that lower power amps of similar design sound better than higher powered amps often through forced simplicity. The exception would be Michael's design, the only SS amp I know of that is limited exclusively by the size of its power supply. Otherwise circuit unchanged, ala S300... I will never hear the S300 monos but I don't need to, it's an unlimited M300.
Michael's design thus is unique. Simple under the hood, but with power. What you are hearing that you like if I had to guess is one of the consistent trademarks of single and dual output device SS designs, they are more coherent and phase correct in their presentation. We are far more sensitive to that than say tonality. I am sure your source produces that in spades already.
Your entire chain is simple yet powerful. A world class tubed AD1865 DAC into 3 gain stage SS monos with only two output devices per side and plenty of reserve for your speakers. Hard to make it any more simple
I doubt it gets much better too, you can spend a lot more money and muck it up far more easily.....