Here’s a stab at it, then. It might be a bridge too far, making her a direct clone. I mean, I get that an opposite-sex clone is possible and Omega from Bad Batch but it might have raised eyebrows in a general audience without addressing it directly.
—-
"Rey….wherever you are…You are hard to find.
“You are hard to get rid of.”
“I pushed you in the desert because I needed to see it…I needed you to see it…who you are. YOU ARE A DARK PERSON AT YOUR CORE. Rey…”
“You’re lying.”
“You were right…your parents were no one. The Sith cult preys on desperate people like them.”
“Don’t!”
“Your barren mother, desperate for a child. She saw a child she could claim.”
“I don’t want this!”
“She stole you from the Sith!”
“No!”
“But taking you caught Palpatine’s attention.”
(Rey sees the vision of her parents and her abandonment.)
“My Love…be brave.”
“You’ll be safe here…I promise.”
“Come back! Nooo!”
“They paid for your protection…in more than one way.”
“Stop talking.”
“Rey…I learned what happened to them.”
(Cutaway to heroes capture)
“Your parents wanted to find Luke Skywalker for protection, looking for his allies in the Jakku desert. Until Palpatine’s assassin(s) caught up to them. But they wouldn’t say where you were. So he gave the order.”
(Rey sees her parents get killed.)
“So that’s where you are.”
“You know why the Emperor’s always wanted you dead. I’ll come tell you.”
…
“Why did the Emperor come for me? Why did he want to kill a child? Tell me.”
"Because he didn’t need you anymore. Once he returned, his clones were a threat to his power. You’re one of his clones. You are a Palpatine.
"THE ONLY REASON FOR YOUR CREATION WAS TO BE A VESSEL FOR PALPATINE’S SPIRIT ON THE SITH THRONE. BUT WE SHARE AN UNBREAKABLE BOND. TOGETHER WE WILL DESTROY PALPATINE AND use his power to forge something new.
(Removes his helmet)
“You know what you need to do. You know.”
“I know.”