Next.js chooses the most optimal devtool for use with webpack. Changing the devtool in development mode will cause severe performance regressions with your application.

Please remove the custom devtool override or only apply it to production builds in your next.config.js.

module.exports = {
  webpack: (config, options) => {
    if (!options.dev) {
      config.devtool = options.isServer ? false : 'your-custom-devtool'
    }
    return config
  },
}