>>/49707/
I see your mistake. Operational can be on brigade or division level, but it starts at the commander of the theater, who can lead even army groups, and ofc air units, but doesn't decides about striking strategic targets (liek factories), which hampers a whole country's ability to wage war - unless the higher ups relegates such decisions to him.
If it's on the front, it's operational. If it's beyond that, it's strategic.
Strategy tends with civilian issues and population too. Operational level is purely military.