Aizen couldv destroyed the Gotei if his arrancar army was as disciplined as the Wanderreich, they were too individualist and the whole meritocracy and number system among the espada created internal conflict
But that’s not what he wanted. He wanted to awaken the hogyoku in the battle against the Gotei 13 so to him whether they failed or not was irrelevant, he’d still come out on top.