From the first OP post I assumed the play was axial, ie the spindle could be moved in-out or horizontally by ~1mm. Now I wonder if
the play is radial (up-down in relation to the ground when the bike is vertical) when the OP says it is limited to the
NDS. The interesting thing about the Hambini vid was the SRAM bearings just slid into place on the spindle meaning
there was noticeable radial looseness. Bearings work best with a degree of press fit, ie not perceptibly loose on the
spindle.
If the looseness is axial and does not respond to rated torque to the fixing bolt then I would try a wavy washer out board of
the bearing dustcap in post
#5 .