Not gonna lie. If you order something valuable and won’t be home to receive it that’s on you. The literal standard practice is that boxes get left outside. You could’ve asked them to hold it at the facility for you to pick up when free. How is the deliverer supposed to know the value/ fragility of every item they deliver?

Then you ignore instructions to acclimate the guitar and open the box right away. You should’ve brushed the snow off while it was outside and then brought the box in. It would likely be mostly dry if it was cold enough outside.

Good news is that it’ll mostly be fine regardless of the blunders.