Problems with baked normal and "ridged" artifacts

Hi, sorry for yet another normal baking problem with Blender 2.8. I have looked at dozens of similar threads but I have not been able to solve my problem. Basically I have this “high-poly” model - some kind of futuristic floor tile - with a bevel modifier applied. Sorry cannot add more than one image.

Which I am trying to bake to a simplified version of the high-poly one, without the bevel modifier.

The resulting normals look very strange:

In particular, look at the oblique indents appear to have those ridged artefacts. Or the gradient-like pinkish area in the top. Also on the right it looks like there are some areas with alternating colors. No matter what kind of ray-distance setting I use, I can only mitigate the appearance of greenish-brownish areas.

Here’s a link to the blend file, I would really appreciate any insight into what is going wrong. Thank you!