Palpatine's plan
So I was having a discussion with someone on youtube, and I realize that a lot of people didn't enjoy Rise of Skywalker's Palpatine because they feel that he wasn't a master manipulator and that his plan in the movie made no sense. But to me, it made perfect sense.
Palpatine always planned to use Rey's body as a vessel. He only told Kylo Ren that he wanted her dead, as he knew that if he convinced Ren that Rey was a threat to him, then Ren would want to use Rey to help him destroy Sidious. Sidious fed Kylo Ren the information about Rey being his granddaughter and having her parents killed so that Ren would use that information to seduce Rey into joining him to kill Sidious together.
Up until Leia brought Ben back to the light, Kylo Ren was unknowingly doing exactly as Sidious wanted. That's why Palpatine told General Pride that Leia had disrupted his plans, because he counted on Ren and Rey coming to Exogol together, and from there would would possess Rey and force Ren to be his new apprentice, which is what Kylo Ren was being groomed for for all those years: to be the heir apparent to Lord Vader.
Palpatine was just using reverse psychology on Kylo Ren.