You've already captured the basic trade-ofs of class-A: the lowest distortion at the cost o vastly higher heat and consequently lower power (since ne needs to get rid of that heat).
Note that there is no fundamental difference between a class-A and a class AB amp. you can take any of my designs turn a potentiometer and voila, go from hgih bias class AB to class A. It will then gradually either burst into flames or blow the fuse (it will do the latter).
A good AB design will in fact be class A for small signals. All "nuance" and "detail" is, by definition, a small signal. So those are class-A anyway in a design like mine, and i am far from alone. So i would suggest that you look for a well designed, high biased AB design as well. I suspect they are indistinguishable from pure classA except by using a thermometer, fire extinguisher, or if you need a bunch of power and headroom ,when the AB will be superior, since the designer can make it more powerful.
I wish i could say "buy mine" but with pandemic shipping and supply chain problems its sitting in pre-production land.
Oh, and "dont fix what aint broke" it sounds like you are very happy. Is there not a better place to therefore put your money? DAC? Turntable? Beaucastel Homage '89?