Today 2019 VW POLO MQB49/5C add key successfully using with Xhorse VVDI Key Tool Plus.
Used KTP for the whole process. Read data with pad, then sent it for online calculation (cost 1 token – must be charged before).
After 3 minutes I got immo data file which automatically saved into the device. After that, you make dealer (used Xhorse proxy MQB style) and program to the car as usual.
Where to buy the tokens?
Here you go:
https://www.xhorse.co.uk/wholesale/1-token-mqb-for-xhorse-vvdi-key-tool-plus.html
You have to use a token to add a spare key from the working key.
Enjoy!