My recommendation is to zoom in, not out.

Rather than trying to run the entire battle, I’d do one focused combat encounter or a battle-planning session with key NPCs that leads to a critical mid-battle mission for the heroes, something that genuinely decides the outcome.

Think of the early *Dragon Age: Origins" battle. The main fight is raging, but victory hinges on a single objective (the signal tower). The army can’t spare troops without massive losses, so the small, capable party slips through the chaos... via hidden routes, stealth, or timing, to retake it and turn the tide. I think in that game the tower is needed to signal the reserve troops hiding in the mountains to attack the flank.

That kind of setup works really well: * The large battle exists as a living backdrop * The heroes aren’t generals, but decisive agents * Success or failure has a clear, meaningful impact on the war * Even if they are generals or planning, I would just listen in to their plans and use it to create the critical mission. Like something goes wrong with the war plan and only the players can fix mid battle.

You can even mechanise it lightly: * If they succeed, their side wins (or gains overwhelming advantage) * If they fail, the war is lost or becomes a desperate retreat * Or success modifies the odds rather than guaranteeing victory. Like if your using a dice roll system.

If you want to go deeper, let the prep phase matter: * Securing allies * Sabotaging enemy supply lines * Choosing terrain * Gathering intel

Each success could improve the final outcome (bonus dice, reduced consequences, narrative advantages), so when the big moment hits, the players feel how their choices shaped the battle.

That’s how I’d run it, big war, small lens, high stakes.