C64's video connector is a very special arranged pin setup. You need the ceter pin if you want to use s-video output.

This is a 8 pin plastic insert that holds 8 pins in position.
You need a donor connector.
Extract pins from donor, replace the plastic insert.

It is a small part, I printed it with 0.2mm nozzle, finequality.
Holes must be drilled by 1.4mm drill for perfect fit
or just pins can be forced in by heat.

There are caves around pins to apply some resin or glue to fix pins if necessary.