Webpack simple bundle no runtime chunk

I'm migrating from rollup to webpack.

I'm building js bundles for browser from some main typescript entry files. The bundles are self-contained and don't require additional dependency loading from them (dependencies are loaded using html script tags).

Rollup did simple bundles, no code overhead (concatenate-like).

With webpack, I'm seeing a log of junk code and I get errors in browser: Uncaught ReferenceError: require is not defined.

Adding the following code seems to solve the errors, but I still see required( method calls in junk code:

optimization: {
    runtimeChunk: 'single'
}

My configuration:

const path = require('path');
const nodeExternals = require('webpack-node-externals');

module.exports = {
    entry: {
        home: './src/Home.ts',
        ...
    },
    module: {
        rules: [
            {
                test: /\.tsx?$/,
                use: 'ts-loader',
                exclude: /node_modules/,
            },
        ],
    },
    resolve: {
        extensions: ['.tsx', '.ts', '.js'],
    },
    output: {
        filename: '[name].bundle.js',
        path: path.resolve(__dirname, 'build/public'),
    },
    externals: [nodeExternals()],
    optimization: {
        runtimeChunk: 'single'
    }
};

Why is there so much code overhead, what's the purpose? Can I remove it somehow?