UNSAFE! Your island wasn't designed correctly from the beginning. You need corbels. Designed into the island. Or, the island top needs to be pulled and install some steel. Or you need posts and stretcher bars. Something.

Until you get support, you need to have some type of temporary 2x4 props or something under it. That can really hurt or kill someone if it breaks.

So just adding corbels and legs won't help?

Granite needs to be uninstalled? Can they even do that? Or do I just deal with the loss

Who did this "design" and where are they? Corbels cannot be installed on top of cabinets that you want to open the doors. Corbels cannot be installed on top of the plugmold. Uninstalling the plug mold would allow corbels on that side, but would do nothing for the long side that cannot have corbels placed there. To place corbels there would require a complete redesign of the cabinetry there. To use stretcher bars and table legs won't really work well with a curved top, but it depends on how much the curve might be. It will limit access to the plugmold, which will get you a red flag from the inspector. It would also need a way to tie back a stretcher bar into the long side of the island. Steel would be the best option, but cannot be retrofitted. The top must be removed.

Bottom line is that this cannot be "fixed" without redesigning it. By someone that knows how to do that. It's a giant safety hazard as is.