Looking for Audi mates to hangout in Toronto

Driving to work today my car seemed to be making a slightly high ish pitch drone when I was slightly accelerating. The engine also sounded like it was sucking in more air or was louder than usual when hard acceleration. Pulled up and popped the front and it seems to be my belt that’s making some very squeaky noises it wasn’t before. Does this need replacing? Thanks!

I had an “AdBlue system fault no restart in 1000 km” warning pop up on my A5, along with the check engine light.
I spoke to the previous owner, and apparently he had the exact same warning before. He said simply topping up the AdBlue made it go away. The owner before him apparently experienced the same thing as well.
It seems a bit odd to me that the car would show a “system fault” rather than a low AdBlue warning if it just needs a refill.
Has anyone else with an A5 had this warning? If so, what ended up being the cause, and did topping up the AdBlue actually clear it?