MQB49 5C key programming on a 2020 VW Tiguan using Xhorse VVDI Key Tool Plus.

Immo data read successfully from the original key and the dealer key generated using VVDI XSMQB1EN remote.
Initial key learning done with ignition off and hazards on as per instructions. Both keys learned successfully with 2-2 confirmation on the dash. The original key worked fully, but the VVDI key would not switch the ignition on, although remote functions and ESL unlock worked.
After speaking with Xhorse support, they advised repeating the process with ignition on. After doing this, both keys worked perfectly with full ignition and remote function on both remotes.

FYI: Solder needle to wake line, will be much easier.