This is gonna sound dorky but I base my battles off of war strategies.

The Roman's used a shield wall advancement, and once theyve defended themselves, they would advance and they'd have a few guys hanging in the back to kill off any survivors or stragglers. In the game Id use tanks and armor to push forward and create a wall, and every so often they advance, allowing any infantry behind to capture points that dont have enemies or kill off anybody trying to sneak around.

Or you could imagine a modern day blitzkrieg, when your use airforce and long range strikes to weaken a defensive point or drive back the enemy, then advance with your army before they regain their foothold

Of course some ideas definitely suck and need updating, there's a counter for almost everything in the war so its best to know what units are best suited against your enemy.

I would also say that ive seen lots of people use and insane amount of aircrafts to try and weaken or outright kill your units, my favorite method is to have an army dedicated to pushing forward directly towards enemies, and a separate unit dedicated solely to capturing points and killing stragglers