The handle (mount) works great !!!

Requires minor modifications - One of the screws for the extruder (lower right) is blocked by the cable holder.
In the pictures you can see the corrected / cut printout of the handle without any obstacles.
I didn't extend cables to the stepper motor. Maybe with very high printouts there will be a problem but at the moment it's OK.
I can say that this is a modification that made me very happy. Now the prints come out perfectly. I changed the acceleration, of course, but the longer print time is compensated for by perfect quality with a retraction of less than 2 mm. ;-).

Here's a movie about how it works:

https://photos.app.goo.gl/CaqyfuskrzsA3CJY6

Thank you very much - MIJU

Ultimaker

Ultimaker 3

Doesn't Matter

Doesn't Matter

0.2

60%