FedEx insurance is outright fraud, UPS makes it slow and really really annoying to make a claim, and USPS' generally it is easier to not bother insurance-wise. My recommendation, to you or anyone else, is to use a third party insurer when shipping things. I have, unfortunately, shipped enough things that I've had to make claims through all the aforementioned, and often times once you find out the "rules" necessary to make a claim you realize that it is absolutely ridiculous. FedEx for example requires that you have photographed the package on all six sides BEFORE opening it in order to make a claim.
The reason I'd recommend a 3rd party insurer is that they have always been the easiest to work with, the most prompt, courteous, and reasonable. In almost two decades of playing this game now, I've never had my preferred 3rd party insurer deny a claim. For them, the business is selling insurance not selling some sort of fraudulent gravy to their primary product (shipping). After all, you have to go out of your way to purchase their insurance, so if it is useless you'll never be stupid enough to use it. The prices are also much much better, again because it can't function as a con it has to function as a good competitive insurance product.
I realize this isn't helpful to you (OP) and I'm very sorry to see the outrageous damage that was done. Looking at it, it looks like the package got caught in automated sorting equipment. I've gotten orders back mangled that badly or worse. The worst I've ever gotten back was, literally, just the label physically cut off the package mailed back to me in an envelope saying "whoops, so sorry we f***ed up, if you fill out this paperwork 8 months later we'll tell you that you're SOL and can go f*** yourself." (yes I filled out the paperwork and waited, just for hilarity)
Once again my condolences. Nobody wins when the carrier screws up. I wish you all the best when resolving it.

Also photograph, or better yet video, EVERYTHING.