Unscrew your cable connection

These have a flexible seal which tightens extremely well against anything with a diameter of 3 to 6,5mm:

Solder wires to your 2x2 socket strip and pin header (not shown here). Put heat shrink tubing with inner glue (about 3cm long) over your pin header/cable and shrink it

Insert cable/socket strips into the screw connector. Shove it into it so your soldered pins are not visible anymore. Back:

Front view:

Add glue. It doesn't need to be totally waterproof on this side. Water won't even get to this side of the connection. It' s more or less to fixate the socket header and cable. Let cool/harden

Plug in your pin header connector, add cap and screw together tightly.

Tight to the max!

Drill a 12mm hole into your enclosure, put in the connector, screw on the washer. Done!