I should've added that GRC is more management, not technical/hands-on, as you may know with your CISSP. Therefore, if you're looking for more technical, don't go GRC.

You'll find that when searching for jobs in either private or government, many jobs of different titles may have the same tasks. Conversely, two or more jobs of the same title may have different tasks. As you said, INFOSEC is a vast field. Despite that, lots of overlap with the many different areas which is a good thing because one of the difficult aspects of our field is plugging in all those gaps in job roles to properly secure a system (e.g., NIST SP 800-181).