I challenge anyone to show theres any significant deflection in a rear triangle on a frame of any material.
Who says it has to be the rear triangle? (though specifically, if I had an Orange frame in the garage just now, it’d be Challenge Accepted, you could twist my 224 by hand)
Simple test- lean bike over, apply foot to side of crank, push. You might be surprised. Or you might have a stiff bike, and not be surprised.
Or, you know, just ride 2 different bikes- if you can’t tell the difference in stiffness between a Ragley Ti and an Mmmbop frinstance with the exact same build kit, then I would be astonished.