Considering that all the corruption checks have been going up (3?,6?,15?,25?) I think it's very unlikely that we are going to see anything from a 0 corruption run, not just because of bailey being around is the "nice" option but you get more lore about the immaterial world and future potential for MC power (he'll be able to bring "back" from there), and then Micheal's dream is "harmless" corruption (ie nobody is hurt you just eat dream monsters) but raises the stat by 5 makes me think it's even less likely that a 0 run will get anything (maybe a line or two of dialog that won't change anything else)I remember a dialogue with Syla during the stormy night, she mentions how you can regain a lot of what the "voices" took from you if you keep in touch with your humanity and find love, i wonder if we will have the chance to purge some corruption eventually for the people who kept it low, or if we will have some margin to work with for a "pure" ending.
If Syla went to the same place MC went (deryl comments on it being shady af but fancy).....then I don't think they were curing monsterism......I figure we'll probably see the organization working on curing monsterism (and that probably treated Syla) at some point. Or some survivor of it, at least, if it's been wiped out. It's Chekov's Gun, WeirdWorld wouldn't have drawn attention to it with Markus Alderman having a scene just to tell us about it if it was never going to become relevant. And they'd be the most likely people to know anything about lowering corruption.
Unless Ella knows MC at some other point in his missing history that's the place they first met, probably where she met tanos (guess based on her looking younger in that photo), and the place where "her plan" was hatched. It would be the biggest twist in the game if they were legit good (or even not bad) people
Logically that group would have to better "monster focused medical stuff" than xanthe since all he can do (with decades and all of heros resource) is prevent corruption if you wear a helmet (for at least 6-8 hours if mc sleeps normally). Curing corruption would have been "helpful" for hero as well considering Henri/Nyx.