It’s like you have to learn every raw CSS selector, and then also learned how it’s represented in Tailwind, and then scatter that all over your markup.That's exactly what it is.
But... you have to do that regardless of what you use for CSS layout. If you're not using Tailwind (or something like it) then you're going to end up creating classes using the raw CSS, and then naming them yourself, and then having to remember what you called them. Hopefully you're good at that and you can remember, else you'll duplicate things. Hopefully your entire team are aligned on the same naming conventions, or your project's styles will be a total mess.
Maybe you'll use styled-components or another CSS-in-JS solution, which helps a bit by making your styles scoped to components so they don't interfere with things outside of where they should, but then you'll have to keep a set of constants to use across all of them anyway, which puts you back at the same problem as plain CSS - you need to remember what's been set, and not duplicate things.
Ultimately, Tailwind is a really well designed abstraction of inline styles that means you don't have to worry about inconsistency and duplication of things any more. It's another thing to learn but because it's so similar to raw CSS it's not actually a lot of effort. It works well.