Booting to Safe or Single User Mode brings up Windows 10 Recovery

As part of trying to repair my Macintosh HD boot volume I have tried to boot into Safe Mode as well as Single User mode. However, when I boot the computer using either of the proper keypress combinations, after a short wait I get this screen. Running High Sierra on a pre-Metal Mac Mini. I have used Bootcamp previously and a corruption of the Windows installation is what started this rabbit hole. The primary macOS Volume does appear when I hold down the Option key at startup but DiskUtil and 'fsck' are having issues verifying/repairing it and it will not boot at this time. Neither will the Bootcamp Windows 10 volume. I did unplug the computer to reset the SMC with no change. How can I properly start my Mac in macOS Safe mode or Single-User mode instead of Windows Recovery?