Printer: Prusa MK4S MMU3

Filament:  Prusament Galaxy Black PLA

I've been trying to fix this x-axis waviness, and am looking for help to understand the issue. 

I've printed this exact same file after each tweak, nearly nothing has changed spacing and waviness. 

The best results I had was to slow the printer down, from 250m/s from the general profile  0.20mm SPEED @MK4S HF0.4 profile, to the 0.20mm STRUCTURAL @MK4S 0.4  profile, (80 m/s) this solution is not acceptable. The waves were still there, just less pronounced but same location. 

I've done these following steps: 

Loosened and tightened the x axis belt, tuned it to 89 hz.  Loosen it to 69 hz, tightened to 120 hz, zero change in the wave pattern.

Cleaned and re-lubed the Z axis and X axis. 

Re-build the X axis carriage (not including the Nextruder)

tested every single screw for tightness. 

Used both my and another's users profile, so no custom changes I've done.

Updated firmware to newest firmware.

Before I pull apart the Nextruder and try to realign the bearings, I'm looking for anyone's opinion on this issue. 

I don't feel any snagging or pinching on the x-axis. Vase mode does not see these waves. 

Any opinions are welcome.