Dual partitioned drives can be difficult to fix as you need to run the tools from a second physical drive.
Do you have access to a second Mac system to create a bootable USB-C thumb drive?
Get a 32GB drive and using the second Mac format it and install the needed macOS this system was running. Then using this drive boot up under it to the run Disk Utility to repair the drive.
Depending on how you are running Windows you’ll need to do likely need to do the same with it.