As soon as someone captures point B there’s no way to captue point C because they spam unlimited units at point B. Trough this massiv amount of units you even can’t barley grap point A for at least a few seconds. So what’s your strategy when the enemy has captured point B and therefor has unlimited units there?
you send single scout units to catch the undefended points. They then have to split up their armies to counter u going to point A and C. If they don’t send an army u can spawn one extra unit if all they sent was their scout unit to stop you. Keep B contested or dwindle his army there down. Try to focus on their weakest units and healing units kill some or even one without losing any of your units retreat back to base to heal. If they heal with support units just know that they cant heal as fast as you can at base. since you’re holding or contesting the side points you will stay in the game long enough for him to mess up. Takes alot of micro managing but try and retreat the units close to death that they seem to be focusing rather then retreating ur entire army. With time u will realize exactly how much of a beating ur single units can take without losing them and keeping them alive with a sliver of health will really make ur opponent rage and over extend. with this plan make ur u take as much energy as you can. defending point B has its disadvantages being that you are further from the supply drops.