(e.g. I was thinking about adding filter for cherry mx key color)
This keyboard is basically the ultimate version of what your list tries to compile: * Ergonomic (split) * Hackable (macros and programmable keys) * Mechanical
https://ultimatehackingkeyboard.com/
It's not out yet, but you can pre-order one.
I agree that most of the keyboards on this list are not ergonomic at all. Most are simply mechanical keyboards.
Is there any science behind this? I don't count "studies" paid for by keyboard makers to be legit --I mean controlled third party studies.