You can try automating search/replace on hex/hsl/rgb values across all your codebases, but targeting "primary button backgrounds on hover" is only possible with some more advanced tooling in place.

And there's an important runtime aspect when it comes to theming, so it's not just about finding/replacing hardcoded values.

But what you need to replace is semantic strings, which "computers" are really bad at finding, and programmers, thinking it's easy, are really bad at adding