I think how the films could be edited all comes down to personal preference. Some might be fine with the ST as a single epilogue film, or as a duology, but personally I would feel like something would always feel missing. Unlike removing Rey Palpatine, which I think is doable, I believe removing Palpatine entirely from the film would be either impossible, or the amount of excision needed would leave the film unsatisfying.
I think the better option is to go in the opposite direction and add elements to the previous films to better set up his revival. Poppasketti has already done this to some extent by adding subtle hints to his TLJ edit, but I could also see future editors adding details to Return of the Jedi as well as The Force Awakens to hint at this as well. If you want to have a nine-film saga, then I think it would be simpler to retcon previous films to improve the cohesiveness of the whole story, rather than almost entirely re-edit the sequel films to better fit the original.
But I can understand why people would want to do the latter. The original films are great, and in a perfect world shouldn’t be changed to accommodate the less-than-perfect sequel/prequel films. But in terms of practicality, it would be easier to to make smaller changes throughout the nine films, including the OT, in order to improve the continuity of the entire saga, rather than attempt to make major structural changes to the sequels/prequels to better fit the sacredness of the original trilogy.
For example, I think it would be better to remove the galaxy-wide celebration at the end of ROTJ to better leave the following political situation more open ended. Maybe hints to Palpatine’s contingency or survival could be added to the various throne room scenes. Or in the case of the prequels, dialogue could be changed throughout the OT better fit what is established in the prequels. This might be distasteful for some, but I think the OT films, whether you watch the GUOT or Adywan’s, or Harmy’s, they will always work as a standalone trilogy in itself that allows you to fill in the before and after with canon, the Expanded Universe, or your own headcanon. But since we have nine films in the saga, I personally would love to eventually see edits of all nine films that makes the entire story feel as natural and cohesive as we can possibly make it.