Here is one mystery that should get cleared up in The Rise of Skywalker. When we first meet Anakin, he is living with his mother as a slave on Tatooine. Once Qui-Gon realizes what he is, he asks Shmi who Anakin’s father is. She tells him there was no father and she just became pregnant out of the blue. Qui Gon immediately recognizes this “Vergence in the Force” and proclaims Anakin The Chosen One. He brings this news to the Jedi Council and they receive it with great skepticism.
In Revenge of the Sith, in one of the best scenes of the entire Prequel Trilogy, Chancellor Palpatine sits down with Anakin in an opera house. He then goes on to tell him the tragedy of Darth Plagueis the Wise. He says that Darth Plagueis was so strong in the Dark Side of the Force that he could create life using the midichlorians. When he says it he kind of gives Anakin a look, strongly implying that is how he was conceived.
The comics take it one step further. In a Darth Vader comic, he is trying to contact Padme in the afterlife. During this time he is under attack from different dark side forces and sees multiple visions.
One of these visions shows Darth Sidious using dark force magic around his mother Shmi, implying that it was the Emperor himself who created Anakin. This can be just brushed off as a vision and nothing more, but the implications are there.
This issue can be answered once and for all in The Rise of Skywalker. The Emperor is back from the dead and if he dropped the bomb on Kylo Ren that it was he who created Darth Vader and is in turn responsible for his existence, it could be enough to push Ben Solo over to the Dark Side for good.