'module' is not defined

I can’t seem to figure out why I’m getting this console error when trying to run my plugin:

vendor-core-98e7eff694049858.min.js.br:15 ReferenceError: 'module' is not defined
    at <anonymous> (PLUGIN_21_SOURCE)
    at <anonymous> (PLUGIN_21_SOURCE:1)
    at call (native)
    at <eval> (PLUGIN_21_SOURCE:3)

webpack.config.js

// webpack.config.js

const path = require('path');
const HtmlWebpackPlugin = require('html-webpack-plugin');

module.exports = (env, argv) => {
  const mode = argv.mode === 'production' ? 'production' : 'development';
  const devtool = mode === 'production' ? false : 'inline-source-map';

  return [
    {
      // Plugin code (Main Thread)
      mode,
      devtool,
      entry: {
        code: './src/code.ts',
      },
      module: {
        rules: [
          {
            test: /\.tsx?$/,
            use: 'ts-loader',
            exclude: /node_modules/,
          },
          {
            test: /\.html$/,
            use: 'raw-loader',
            exclude: /node_modules/,
          },
        ],
      },
      resolve: {
        extensions: ['.ts', '.js'],
      },
      output: {
        filename: '[name].js',
        path: path.resolve(__dirname, 'dist'),
      },
    },
    {
      // Plugin UI
      mode,
      devtool,
      entry: {
        ui: './src/ui.ts',
      },
      module: {
        rules: [
          {
            test: /\.tsx?$/,
            use: 'ts-loader',
            exclude: /node_modules/,
          },
          {
            test: /\.css$/,
            use: ['style-loader', 'css-loader'],
            exclude: /node_modules/,
          },
          {
            test: /\.html$/,
            use: 'html-loader',
            exclude: /node_modules/,
          },
        ],
      },
      resolve: {
        extensions: ['.ts', '.js'],
        fallback: {
          fs: false,
          path: false,
        },
      },
      output: {
        filename: '[name].js',
        path: path.resolve(__dirname, 'dist'),
      },
      plugins: [
        new HtmlWebpackPlugin({
          template: './src/ui.html',
          filename: 'ui.html',
          chunks: ['ui'],
          inject: 'body',
        }),
      ],
    },
  ];
};

Pretty new to plugin development so not entirely sure even what to look into. Any guidance would be insanely helpful!