I think the best idea to retroactively tie the sequel trilogy films together is by doing it the subtle way. For example, the brief Palpatine hints that are scattered across the Rekindled edit of TLJ (like his silhouette at the cave scene, his laugh during Luke’s flashback, or Snoke’s eyes turning yellow after he’s mortally wounded), that culminate in Palps’ “find me” at the end.
For example, the vision in TFA would be a great part to put a hint of Palpatine’s involvement, like the shot where young Rey watches Ochi’s ship depart Jakku.
In my cut of TFA I add the chanting of the Sith cultists and Palpatine’s laugh to Rey’s vision. I also adjust her conversation with Maz to take out the “There’s still someone that could” and Rey’s assumption that Luke is her father.