One more critical step!
Restore to assets/js/app.js the line:
import "../css/app.css"
or equivalent.
This is needed for esbuild to automatically bundle the CSS and write it to the same directory as your app.js (as documented in deps/esbuild/README.md).
At least for our project, after following the upgrade steps, that line had been removed, and although we did not need it for actually using the CSS we needed it for esbuild to do its work.
As for core_components being polluted with tailwind classes, i agree, but we are informed if we want to change the classes in core_components we need to override each one.
