I use a PTFE tube from the filament dryer to this connector and from the connector to the extruder. You can just clip this to the frame of the MK3S+ and then clip a connector such as the one in the picture to it. Prints well without supports, I used PETG and 3 perimeters. You can also print it with supports, if you want to print the clips that hold the connector on the print bed for extra strength.
The author remixed this model.
It fits a bit tighter to the frame and has the clip for the pneumatic coupling connector