This might be the best possible way to save this trilogy in the most gentle manner there is. I love it and already consider this could be my new GoTo-ST.

Just three things:

In the crawl for TFA, I wouldn’t call this returned ancient evil familiar just yet. That decreases the room for suspense.
Just like Dr. Krogshöj sayed, make Snoke either a clone made by palpatine or maybe a dead body (e.g. the exhumed body of an anccient sith-lord, but this doesn’t even needs to be deepend) occupied by Palpatine. But make it a mere vessel controled by Palpatine rather than a moreorless independend individuum driven by his own will.
That said, I’m totally pro Clone-Palpatine. The real one died at the end of VI. The clone was created by him as a safety blanket (stashed secreatly on Exegol, treasured and then activated by the cultists).