I anticipate that it could be fun, but most players are D&Drones that can't imagine playing anything other than 5E. The GM would have to manage expectations.

The way I see it, such a game would involve alternating "Domain Turns" and traditional D&D, and "Domain
Turns" which represent three months of in-game time, and end up looking more like some combination of Risk, Diplomacy, and Axis & Allies.

In between Domain Turns, the players will be doing their normal murderhobo thing, going on quests, doing diplomacy and espionage at foreign courts and killing monsters.

This would be a pretty cool campaign, right?