Literally the first line says that it's a component library :)

Snark aside, I'm gonna defend Radix Themes. I agree that the configurations they show on their website aren't great (and also that they should pay more attention to pixel alignment), but they have the most consistent structure I've seen, with well-defined tokens, great composability and flexibility for overrides.

I've found that, with the parameters they provide, I can get a design that is close to what I would've done myself anyways. Eventually, I guess I'll look into adding some light overrides to add a bit more shadow and fix some of the rougher edges.