I tried to shrink my Windows Bootcamp partition using third-party software which led to my Macintosh HD partition missing from startup options. Unfortunately I don't have a recent backup for the whole drive to restore from. If I try to reinstall macOS from scratch it doesn't see the partition either.
Disk utility sees it but it's greyed out and is being shown as Unmounted without the option to mount it back.
Is there a way to fix this without wiping out the whole drive and reinstalling everything from scratch?