You can use this 3.5mm headphone audio soldering jack to make any 3.5mm cable by yourself
These 3.5mm Stereo TRS 3-Ring Plug Connectors are suitable for audio video application that require TRS Plug like cellphones
Suitable for the cable up to 6mm, if your cable is too thin, just use some sleeve to hold it properly to avoid the movement
Easy to handle,you really don't have to be a professional to do this. Just insert the cables in the hoops, twist and lock in place, and only then solder.