Parametric AMPS pattern plate with ball for socket for phone mounts in cars.

Fusion parameters can control hole diameter (¼"), the ball's center offset from the plate top (9/16in) and the ball diameter (17mm).

Improvements you might want to make is add countersinks for whatever bolts you end up using.

Printing modifications you probably want to increase strength with more wall loops and/or more infill as the ball will see load.