Hello,
There are a few things you can try, you already mentioned setting $APO.CDIS, however note that the highest value will be half the point distance - so if your points are closer than 40mm, your 20mm won't really have an increased effect.
If you want constant speed, consider setting the movement to C_VEL and using a high $APO.CVEL value (oercentage).
Also you could try using a spline movement, though I'm not really a fan of it.
However, the main issue is probably the A4 turning, which means that you are probably close to a singularity, i.e. the robot is stretched, in your case likely with A5 close to 0.
If you have a symmetrical tool like a pen or a milling tool, then rotate the planes around their tool axis, e.g. with the Orient Plane component. Alternatively change the position of your toolpath if you can, e.g. moving it up or down in relation to the robot.
Best,
Johannes