Early game ground combat is problematic as it pretty much autocannon spam meatgrinder till you get actual fun equipment like tank cannons and artillery, before that you have to over rely on your airpower otherwise the vehicles will get slaughtered. Adding mortars for light/medium chassis will help to diversify early game combat a bit. Mortars should be much shorter ranged so you cant just keep it off-island, with faster aiming time and faster projectile delivery to quickly respond to threats. Mortars will be great at rapid indirect fire support, while regular artillery is good at preemptive bombing.