Did Rey flew Luke’s X-Wing without an astromech droid?
Yes, but I’m assuming the Wayfinder may have fulfilled that need. Luke also reached Ach-To without an astromech, so either that X-Wing doesn’t need an astromech or maybe both Rey and Luke used the Force to guide them. Or a mix of both.
Luke used a Jedi compass to find Ach-To. As explained page 53 of The Rise of Skywalker Visual Dictionary. And the story of how Luke got hold of this Jedi compass is told in one chapter of the solo campaign of the video game Star Wars Battlefront II.
But why and how Luke drew a map to Ach-To, hid one part of this map in R2-D2 and the second part in a USB drive kept by who-was-this-guy hiding on Jakku?
There’s another thread where we’re discussing this exact topic. According to Abrams, R2 inadvertently downloaded the Ach To map from the first Death Star. Lor San Tekka was a member of the Church of the Force, so I’m guessing their map fragment was something they had in their possession. He’s also supposed to be a former explorer, so maybe he found it in a Jedi temple years ago. The map is supposed to be a map to Ach To that was created long ago, it’s not something that Luke made. None of this is made clear in the films.