when you make the exo build, you dont make a frontline and depend just on micro try to put some lancers, vulkan or similar also, the infantery healer, dont just heal and put a dot of heal, but that dot gives armor, so it makes the frontline much more resisilient, you dont have to ugrade it if you dont use mech (the second skill just heal mech) and there is one air vehicle suport for vanguards that is quite bad, but the second skill it have is a big buble that shields infantery againts 75% of ranged damage, its amayzing againts gaunts ball and you just need one of them