I was thinking of a similar point but you beat me to it! But, I will expand.
I too found the medicine situation odd (or at least out of place) - though I’d note that for the most part it does seem like we’ve mostly been playing in an absurd version of the 1800s as opposed to a future recreation of the 1800s, and perhaps that’s the head-space messana is in too.
My impression was that messana went on a Regency novel/movie/TV bender and got excited about it and wanted to make it work as a Badass game and came up with this Charybdis mash-up, but primarily rooted in the real thing.
I am into media about the British in the 1800s too and I’d like to point out that mysterious illnesses and plagues are a rather common plot element. But, importantly, mysterious illnesses and plagues are also a common plot element in a lot of science fiction - numerous ST:TNG episodes immediately come to mind, for example. In those kinds of stories, despite advanced medical technology, the illness is able to take hold and spread (at least for a while, until the characters figure it out). So I think it’s a reasonable thing to have in the game.
Snake-oil cures do also sometimes exist in those kinds of stories, but I think in our story here it felt odd because there was no indication that anyone had actually tried modern medicine on the plague, and no broader suggestion that in this world people outright reject any aspects of modern technology or that it’s unevenly distributed (a la Firefly) - it seems like the recreated society was created as sort of a backlash against purely social aspects of the broader society, not against modern technology.
It does still have a whiff of foreign-auto-repair about it (i.e. arbitrary restrictions that don’t make sense in the setting), but we haven’t really seen how it will play out. Chances are, though, that we’re reading far deeper into it than messana expected. So, @nimelennar, I have to say I have enjoyed your role-playing as a plague-ridden character, but you also have the option of steering the story towards something that makes more sense to you - the “yes, and…” principle, which we know from experience messana will go along with, so long as it doesn’t break the base mechanics of the game.
So this is all really a gentle reminder that you can come up with an explanation for why the plague exists that you like better - your character is stuck inside, after all, and has free time to research things - and it will become canon.
I say all this because these kinds of player-led changes/additions to the basic setting are typically some of the most interesting, exciting, and enjoyable aspects of these games, and it really seems like you are worked-up about it enough to have the motivation to do it - and you’ve demonstrated really rather clever and creative writing already.