Understanding how Ionic 5 uses colors

I’m really struggling with colors in my Ionic theme. The default app had a bright white and blue theme but what I need to achieve is a dark grey theme. I have found the “Color Generator” in the docs but it doesn’t affect background color in any way apparently? Or text color? So I tried setting “light” to a dark color (which felt wrong, but for science) and that didn’t work. From combing the docs I found a few more variables to add, like --ion-text-color and --ion-background-color which affect some things. Do I really need to manually set up the *-tint, *-shade, and *-rgb variants of every color by hand? Is there a 3rd party theme generator?

This is a lot of questions but it’s hard to nail it down to a specific - I just feel like I’m completely missing the point about how Ionic themes are supposed to work.