Here’s how I might restructure the villain’s plan for the trilogy:
TFA
The crawl establishes that the First Order is intent on killing the last of the Jedi. This is the most important thing for them, though it is unclear why.
The Starkiller is multi-purpose. The interior has been hollowed out through mining to supply the ores necessary for the First Order/Palpatine’s fleet. After this it has been retrofitted as an experimental weapon by ambitious First Order leadership spearheaded by Hux. The fact that it was first used as a forge could be a mystery in TFA or only hinted at, but explained later on.
After Kor Sella is sent to the Senate the base begins charging, and everything from Restructured happens as planned except that the base is destroyed before it can fire like in the original. The Republic is not destroyed.
There are hints as to the true size of the hidden fleet and their provenance, perhaps placed into one of Rey’s visions or in Kylo’s interrogation of Poe.
TLJ
The crawl establishes that Kor Sella’s mission to the Senate has been a success and the Republic is in the process of relocating its fleet to D’Qar to bolster the Resistance forces.
However a Star Destroyer appears before the fleet is fully assembled and wipes out the planet (This uses footage from TROS and TFA). Only a few ships escape to join the Resistance, and these, we later learn, were tracked.
Cut to the island where Rey tries to convince Luke to join the fight. She doesn’t know that the Republic is gone, so doesn’t tell him that the First Order is on the verge of victory. Since Luke isn’t connected to the Force he can’t feel such a loss anyway.
Cut back to the Resistance base and Hux’s forces arrive to cut off their retreat. Cut the jokey attitude of the Resistance characters to match the grave knowledge that the Republic has been destroyed.
The film carries on much as before except that the final scene shows Kylo Ren finding Palpatine and his fleet instead of showing the Broom Boy scene.
TROS (or THE FINAL ORDER)
The crawl states that the First Order is moving quickly to gain control of the galaxy.
The first scene is Palpatine’s message to the galaxy. The full threat of his fleet is revealed.
Our heroes rush to find the Sith artifacts required to locate the Sith planet, etc.
The defeat of the First and Final Orders shows a montage of planets rejoicing, prefaced with Broom Boy relating Luke’s inspirational visage which reignited hope in the galaxy. This is bookended by him walking outside and seeing a First Order Star Destroyer broken and burning in the night sky above.
Rey visits the homestead. End Credits.