[2020] How to take down a Star Destroyer

So I'm doing the Fleet training mission and have eliminated all other enemies and gotten the star destroyer to 1 health and it's a flaming pile of debris. But I can't destroy it after an hour in the match!

I've even destroyed every turret, missile launcher, shield generator, tractor beam, targeting system, etc that I can find and destroy (though there seems to be some laser turrets that are invisible and indestructible, I guess so you can't ever just fly around it safely).

Any tips? There's no other visual HUD or help or info to know what to do.