Considering those facts, and the fact that the entire Sequel Trilogy takes place over the course of only a year, makes me feel like if you made a trilogy edit where most of the action takes place beyond New Republic territory, and the Republic is never destroyed, it wouldn’t really impact the films that much.
Yes, we see the Republic planets blow up, but we don’t ever see how that effects Republic worlds. The whole trilogy could take place within the First Order’s small territory, with the Resistance being a covert operation within its borders. No Starkiller, no Snoke even. Just a radical Imperial remnant who use the heir of Vader as a figurehead. The hidden Imperial fleet could be their key to conquering the Republic, but then it’s the Republic fleet that kicks their butts at the end of the movie. Sure, we would never really get to visit the New Republic, but at least it wouldn’t be conquered and then apparently restored off-screen.
It’s just kinda nuts that they made a Sequel Trilogy and never really gave us a good look at the actual New Republic. But then again, if you keep in mind the trilogy only consists of a single year of galactic history, then it might make more sense if the First Order’s scale and off-screen blitzkrieg of the galaxy is downplayed, or entirely removed. Maybe less dramatic, but it might make the ST feel less like a reset.