I think it would be a lot easier to re-edit the Tusken massacre as a dream sequence that happens after he brings his mother back from the desert.
You’d only have to insert a new line in his confession scene, perhaps covering it with a reaction shot from Padme:
“I killed them. In my dream. I killed them all. Every single one of them.”
This would keep Anakin’s intense feelings while bringing the experience into a realm which is deeply relatable for anyone who has suffered loss. Padme’s words would fit this situation perfectly, while also showing how Anakin is unable to square his feelings with his upbringing as a Jedi.
It would also work to deepen the line from Palpatine later since it confirms that Anakin trusts Palpatine enough to share his dreams and nightmares.