Any way to boot after improper update?

I ran the 12.6.7 update on my 2010 Mac Pro. When it rebooted to apply the update, it defaulted to booting back into the OS, not the update process. This left my Mac Pro unbootable on that drive.

Is there a way to easily make it bootable again, or do I just have to reinstall the OS over the drive?

Thank you!