.........................but I want to believe that my most magical bikes are products of alien technology.

Also, I weigh in the 220# - 235# range, so getting a butted tubing bike frame to flex is not difficult.
You ought to look for something in a very lightweight tubeset, like Tange#1 (used in some of the
Centurion Ironman bikes for instance) or whichever Ishiwata was below 022(019?).

Besides your weight , you probably ride a smaller frame, so also a stiffer geometry.....

I agree that a lot of what is referred to as "magic" is flex (but not too much) coupled
with rigidity (but not too much).........and that it varies with a personal anatomy to some extent.