[LexxM3]

Another idea, but only after battery is guaranteed to be fully charged, is to VO code the entire car. Or maybe do one ECU at a time and see which one gets fixed, if any (will take a long time that way, there are something like 42-46 ECUs in the G05/G06/G07).

If you're familiar with ESys, you will already know what that means. If not familiar, I would only go down this path if the dealer visit so utterly impossible that you're willing to try anything else at all. To be sure, VO coding with correct cable, ESys setup, psdzdata files, and battery power supply is pretty safe, but it does seem extreme and may not work anyways if you need FSC coding in the end.