Is it still detected if you place it in the emergency backup slot and try to start the vehicle (if it isn't detected if just inside the cabin)? If it is, I personally would buy a used OEM fob off eBay to replace it. You need to make sure you get the right one (remote start or not), and make sure you already don't have 4 keys programmed in.
I picked up an OEM fob for $30 off eBay, but unfortunately the previous owner lost 2 keys, so it has 4 programmed in already, so I can't simply add one.
There are replacement cases for them, but I can't tell if you can non destructively pull the case apart or not, it seems sonic welded but I don't have one to sacrifice to test it. I only find videos for other keys, mostly because they are more likely to be broken than these.