How to build BOTH non-block components and blocks present in the /src directory using @wordpress/scripts

Just add a webpack.config.js file at the root of your project with the following contents:

const defaultConfig = require( '@wordpress/scripts/config/webpack.config' );

module.exports = {
    ...defaultConfig,
    entry: {
        ...defaultConfig.entry(),
        index: './src/index.js',
    },
};

Ref: https://wordpress.stackexchange.com/a/425349/195680