Webpack - admin stylesheet

Apparently webpack in watch mode will remove the styles/ folder in dist/ and rather dynamically inject the styles.

This works well with the main stylesheet - but it doesn’t work with e.g. an admin stylesheet.
The theme adds an admin stylesheet to adjust some UI components for reflecting the result in theme better.

The admin.css is enqueued in acf/input/admin_enqueue_scripts - but webpack doesn’t inject it when watching - hence no styles are applied.
How can I let webpack inject it, too? - Ideally only when it is enqueued?