The clips supplied with the general car mounts don't hold well and that bothered me.
Inspired by various similar holders, I came up with this version, which can be printed horizontally. The horizontal printing position improves the stability.
17mm ball diameter
I recommend to print it in PETG or ABS. This allows the parts to withstand the temperatures in the car better.
No support material needed.
I give credit for the main ideas to the following designs
CAD Model
Phone Mount used in the picture:
https://de.aliexpress.com/item/1005006072036385.html
The author marked this model as their own original creation.