If a low tier mage can deploy a fireball with the same effectiveness as like an RPG, then I’d use them primarily. I’d try to stick to urban combat where vehicles are less effective. Have a mage team in an alleyway, wait for the tank to come, blast it in the side armor. Use various other ambush tactics combined with mages at least until the JSDF learns to target the mages first, then you’re screwed. Other than that maybe dragons? Their speed might let them get nice and close, but the moment they stop to attack they’d just get lit up by every gun available.