Summary

I split the original design from gre05 (https://www.thingiverse.com/thing:5723230). That way one can print the ball part horizontally, which makes it much more sturdy when the Garmin Display is moved. Downside is that you have to print it with support
Despite that it is a relative tight fit, I would recommend to use some glue.

I also increased the diameter of the ball to 22mm, which fits the Garmin Camper 890. Will probably also fit the 895 and 1095 versions.