Thanks. It was me being worried about spoilers by looking at trophies so I neglected to know that I needed to talk to the Principal for a choice of a Master Quartz at the end of the game. Then during my second playthrough I forgot "open all chests in one run" was a thing so in
(Chapter 5) where a trap chest had a master quartz I was like I got that last run, I don't need the Zeram Powder or whatever it was and it was the only chest I didn't open.
Derp.
I was looking at what carried over to CS2 and I saw that level 80 for Rean was needed for the maximum bonus for that... it took all of the final dungeon to get me from 70.5 to 71 without skipping fights, that grind is not happening.