“The cave! Remember your failure at the cave!”
“But I’ve learned so much since then!”
IMO, that bit of dialogue hints that something more than two weeks worth of training passed by.
That’s a very good point and I hope he got at least 2 months of training. That would explain why someone who has never been trained in actual lightsaber combat was able to land a hit on a Lord of The Sith. There’s no way 2 weeks of could explain why Luke was able to hit an undisputed master of lightsaber combat.