Worth taking the battery off the car and charging it possibly.
We have a 2017 Audi A6, probably very similar electronics to yours, Christmas eve the battery went flat and it reported all kinds of failures, entertainment system, electric boot, emission control.
It’s worth checking with VW. We called out audi assist who replaced the battery FOC as there was a technical bulletin issued. Start stop batteries are expensive, around £200 and need coding to your car to be fully effective.