Clearly the message of the Disney Trilogy isnt about training. So if you're looking for one, that's not the right place. Because I realized it early, I stopped looking for an underdog story in the Disney Trilogy.
While MHA and OP are your epic underdog, with hard work and a bit of luck you can create miracles story, the Disney Trilogy is NOT.
Rey's story is the "I give you OP powers, now stop whining and do something" so I stopped caring how she got it. Which is why to me, any kind of vague 5 minute training montage is sufficient because it was clear the writers wanted to show her off asap.