Another think to check is the rear speakers. The seals fail allowing water into the car. I’ve had two mk7s now, both bought at 3 years old and both had this issue.
What’s the tell tale signs to look for with this issue ?
Damp carpets and damp sound deadening material under the carpets as a result of water draining into the cabin around the speaker seals. If this is left unattended, I believe any water ingress that soaks down through the carpet in the rear footwell can also run forward into the front footwells, resulting in damp carpets / sound deadening material in the front footwell too.
If you Google ‘mk7 Golf failed door speaker seals’ or similar search, you’ll get a few results returned where owners have had this issue.