This will probably get lost in the splurge of other posts but maybe someone might read it
One of the big complaints about Rey in TFA and TLJ is how come she's so dam good at everything, well I have a theory, it goes something like this.
Suppose I am a fully qualified engineer and I can strip and rebuild an engine in an afternoon, now I can do this because I have had years of training, years of experience putting my training to use I know what tools to use and how to use them, I even have the 'muscle ' memory in how to use them.
So, lets say a telepath comes along and wants to strip and rebuild an engine in an afternoon, they could just 'copy and paste' all the required knowledge, training, memories etc. direct from my mind to theirs and hey presto they can do it.
Now back to Star Wars, in TFA Kylo is probing Reys mind to find the image of the map she saw, my theory is that during this probe two things happen, Kylo inadvertently flips a switch so to speak in Rey that turns on her force power or at least makes her able to access it and in that time Rey 'downloads' all the force knowledge, training, memory's, techniques that are in Kylos head – it was already established that there was two way communication so it wouldn't be that off base – all this knowledge is not right there in her conscious mind where she has immediate access to it but is there in her subconscious and it slowly 'leaks' out as she begins to process everything.
She starts small with the Jedi mind trick, you can tell she's not quite sure what she's doing or how she's doing it but that's her mind accessing what's been downloaded into her subconscious.
This kind of theory could also have been given credence in TLJ if Rey had done something on the island, a fancy lightsaber move maybe and have Luke ask
“Who taught you to do that” to which she replies “Nobody”
he then rushes of to the sacred writings flipping through them and pointing at a page and explains to her about an ancient Jedi force technique allowing the direct transference of knowledge from master to pupil but that it had been banned by the Jedi council because it could lead to the dark side or unforeseen consequences or side effects or some such thing
I know it's reaching and I did just think it up today so its probably flawed but it 'might' explain things?