Decided to just flip all of the switches, Gravity wells, ice and space junk, and make the battles fair.
Four interceptors and one Claymore, all.
I have played many battles by now, and I have two main behaviors I am looking for. In this case, I noticed the enemy is trying to flank behind some ice, so I quickly send my swarm over there to eliminate the squadron. This is simple math, as soon as you eliminate one squadron, you already have a math advantage.
The enemy always tries to close flagship distances. The enemy flagships is very strong, as strong as a battleship, and it's much better at driving them than I am. They look faster and more responsive on the AI's team. These might be due to racial bonuses. So what I try to do is position space objects between me and the enemy, to absorb the incoming missile fire.
In this case, it works wonderfully. I already had the advantage by one squadron, and now I have neutralized the flagship. The rest is in the bag. Victory.