PROJECT PRESENTATION
I share with you the source files allowing you to make a solid ball and socket connection  to reuse in your designs.
This version is the result of a long series of iterations to find the right design.
This ball joint allows to have a displacement of 25° from its axis, and at 360°.
I used it in my design of phone support: https://www.thingiverse.com/thing:4694593
This includes .step files and files from Fusion (.f3d).
I hope this will help you in your future designs!
Reuse it well!  
UPDATE 11/02/2020 (V3 files)
Better sketch in Fusion 360 with more constraint (will less go messy if chnaging dimensions)
Larger walls for the base to avoid printing problems
Shorter link on the ball joint to reduce overhang
Bigger displacement (about 30°)
V3 files are 100% compatible with files of the first version