Summary

Like many others, I have come to the conclusion that it is not possible to print TPU on an Anet printer without preparations. As expected, I found solutions to my problem on Thingiverse. Once again, the solutions didn't fit my printer perfectly.
And so I started to design again, based on the solutions of MasterFX, Bomber0 and Leo_N. With the offered STL files I have noted deviations to my printer in the tenth to millimeter range, which is too much deviation with such a delicate constellation.
I marked this thing as a remix because of the sources mentioned above, although I redesigned it from scratch.

Printer settings:
Material: PETG
Resolution: 0.1mm
Wall thickness: 1.2mm
Top/Bottmom thickness: 0.8mm
Infill: 100%
Support: no
Build Plate Adhesion: Skirt