I don’t know who these "upper shelf designers" of amplifiers are that you’re referencing. Okay, you find your tube audio electronics "colored" (As though transistor audio electronics don’t have their own colorations, albeit different). If these are your conclusions based on your experiences, Then I accept them as "yours".
I’m in no position to challenge or refute what you’ve experienced. I can just simply say that you and I have had different experiences and as a result, different outcomes that shape and form our respective opinions. I hope that you are able to obtain an amplifier made by one of the upper shelf designers that you cite above.
I meant what I have written earlier, follow the pathway that suits you the best. My chosen pathway is to hear and do actual listening of audio products myself. If you are reassured by test measurements then continue with that method. For me it’s woefully inadequate.
Charles