Reylo

Light, Darkness, Balance

In the phantom menace we learn that Anakin Skywalker who would one day become Darth Vader, was the chosen one from a prophecy who would bring balance to the Force.
Some say that Anakin wasn't really the chosen one from the prophecy, because he turned to the Dark Side. And that even though he did defeat Darth Sidious, he couldn't have done so without Luke.
But he did defeat Darth Sidious. And he did bring balance to the Force, even if it didn't last. Therefore the prophecy did come true and Anakin was the chosen one.
Anakin did fulfill the prophecy, and bring balance to the Force. It just didn't last.
As you know, Anakin became a Force ghost at the end of the Return of the Jedi.
As a Force ghost, it is only logical to assume that Anakin has been watching the happenings in the galaxy, ever since. The same way Obi Wan did. And Yoda who even appeared as a Force ghost in the Last Jedi.
Anakin most likely saw everything that happened in the galaxy after the return of the Jedi. He probably watched the balance in the Force slowly crumble, until it was gone again. He probably felt that he had failed, that he not fully brought balance to the Force. That he had never really accomplished that task in his life.
When darkness rules, light always rises to face it. When light rules, darkness always rises to face it.

"Darkness rises, and light to meet it."-Snoke, the last Jedi.

Every time one side of the Force is defeated, it always rises again. It never brings balance. It has been a constant pattern in the Force. One side rules, then the other side rises to defeat it. And again and again. It could continue forever with only brief moments of balance that never lasts.
The only way to bring true balance is to set aside both the Light Side and the Dark Side, leaving only the Force. The only way to do this is to bring the Light Side and the Dark Side together. The answer is not destroy both of them. Because the only way for there to truly be balance, is to have both the light and the dark sides of the Force working together.
But now that the Force is no longer balanced, as the chosen one, Anakin would see it as his duty to bring balance to the Force.
What if Anakin was behind EVERYTHING?
What do I mean?
What if Anakin was the one who caused the connection between Rey and Ben?
Both Rey and Ben have something that once belonged to Anakin Skywalker.
Ben has Darth Vader's helmet, which was the part of him that was on the Dark Side.