Yeah, I know what you mean.
Unfortunately many areas of accessibility don’t have such a one-size-fits-all solution. Low, medium and high contrast themes in both light and dark mode would be a good starting point and allow at least minimum use for most people, but it would still exclude many people. If you’re adding more themes than just light and dark mode, is it that much more time consuming to add customisable themes? The iOS Mastodon app Ice Cubes is open source and has similar theme customisation to Arctic, I’m not sure if it could be of any help.
‘Problem/solution’ is appropriate wording for technology, no one will interpret it ableistly! Inaccessibility is a huge problem. I’m not sure anyone feels fine just the way they are when they’re excluded from the majority of the internet and society at large though, haha.
Not a huge fan of correlating mental health and capitalist greed, personally.