Five months later, I finally went back and finished the last boss rush on Easy.
True to its name, this was dramatically easier. It was still an unpleasant experience (I really hate the last fight with the bosses that keep respawning and the cinematic attacks that completely break up the flow of the fight, not to mention the difficulty of Sephiroth making you do it all over again when you die...) but I was able to cut through it on the first try.
I've finally (finally) unlocked the Yuffie DLC which was the entire reason I was replaying it on PC to begin with.
Not sure when I'll actually do that (real-life has completely ruined my headspace for the foreseeable future: it's a mess in there), but I am happy to finally (finally) have it accessible.
I'd played the based game through on PS4 when it came out but never did the DLC.
It's finally (finally) almost time.