I don’t know who would pay thousands of dollars for an old shit, but I’m quite certain they ain’t my kind of people

Yeah this is the way. I honestly forgot they had ads until I pulled a video up on my phone to show a friend the other day.

PolyTerra Matte

This is a mechanical issue with your motion system, not your bed. If it were the bed the probably would not be consistent between different bed surfaces.

I would make sure the roller paths are clear and flat the entire length of the path. More than likely that is the cause. Also check that the cables are sufficiently long so they aren’t putting excess tension on the tool head or bed at the extents of travel.