Seven factions, two wars, one battlefield. Devastation is IMMINENT...
When you have enough men to spam why not turn them into human anti-tank mines? Suicide Bombers use their fast speed to catch up to tanks and detonate themselves, destroying or at least severely crippling them. They are also perfect for disorienting squads of infantry and taking out base defences to pave the way for other troops.
I like how you're trying to make Infantry have a use. =)