Symptoms suggest something wore like the rear u-joint causing a wobble that's beating up the CSB.
You replaced the giubo so I'd look the other direction.
You can set up the likes of GoPro (I use my fiber optic camera strapped in pointing at what I need and it's wifi so I can record video or take pictures.
https://xoutpost.com/bmw-sav-forums/...joint-e53.html
I've found threads that talk about it and others that show how to replace just the u-joint on other "non serviceable" u-joint BMW.
I found one link to a place that you can buy just the u-joint if you can measure exactly the size you need.
I did not find the answer to that but it's out there. I can't think of anything other than worn u-joint or bent prop shaft that will cause your symptoms.