I’d be interested for the DataPlug from Audi as well. In my opinion they should work quiet similar and Skoda provides a DataPlug as well so maybe those 3 could be combinded into one integration somehow.
For the VW custom_component there is an inactive issue for this with no decision yet: Support for We ConnectGO · Issue #309 · robinostlund/homeassistant-volkswagencarnet · GitHub
I’m using my Audi DataPlug for one week now and according to their data privacy policy they only transmit the data to their servers during a manual/automatic “full-backup”. With my very basic non-existent Wireshark skills I was not able to get any meaningful content during the backup transfer (could be possible that it’s transmitted as binary/encrypted as well).
I think the new first level Bluetooth features of Home-Assistant since version 2022.8 could be used here instead of cloud polling as well to at least get some useful data like tank level and mileage when the car is parked near the Home-Assistant system. (The new ESPHome Bluetooth Proxy could easily extend it to a garage.)