I did the same mistake with the battery and definitely have the same steering issue and alarm sounding off. What was the outcome of your MK. It helped alot as I already checked most if not all the fuses and not getting nowhere. Hope yours was fixed.
Had the same mistake happen with my son's car - 2015 mk7. Anyone come up with a fix for this? Worked through the fuses and still a problem, thinking of the relays next?
I made the mistake of connecting the battery in reverse polarity. This is what happens to your main fuse. See pictures.
There is more information at the beginning of this thread.
I did this as well. Replaced the alternator and blown fuses, however my lights are not working properly (F&R), no pwr steering. I’m at a loss. The dealership won’t touch it unless I put the whole car back to OEM.