His utterance regarding his resignation is a pure s@%t of a bull.
Nothing new and shouldn't be taken seriously and you're right he cant do it since he doesn't like Leni.
His message is clear to me.
He will step down IF he will be replaced by the likes of Bongbong Marcos or Chiz Escudero.
Since Leni Robredo, whom he labeled as weak and ineffective, is still his legal successor, he will NOT resign anytime soon.