VCDS is what you need.
A genuine second hand HEX-CAN is about £200. The newer V2 or HEX-NET are between £230 and £650 depending on number of VINs it can be used on (the mk3 doesn't have a VIN stored in any ECU so that doesn't use any up).
Stay clear off the cheap eBay knock offs, hardly ever work correctly and it's usually the Chinese copy mafia you support. Personally I've started to stay clear of anything coming out of the PRC (people's republic of covid).