Hard drive suddenly unformatted, can’t get macOS to load

I just updated my machine with the latest update. After restarting my iMac keeps loading windows through boot camp. I can’t get into my Mac. When I look at the hard drive using disk utility, there is 1.7TB that is unformatted while the other 300 is for windows.

Does anyone know how to fix this? I ran first aid repair and it was completed without any errors.