@Phaedrux Extruder motors are not affected by M569 B, F, Y, as the second part is commented out.
@theruttmeister I'm past this phase of troubleshooting. I was printing at basically 20-30mm/s. The hotend is rammed so hard that the molten plastic is flowing upwards, I'm sure of it.
Also, a low value of S0.05 should not cause so much extrusion.
Please, someone follow my request and try print this on a CoreXY Bowden.