I followed a guide to enable sourcemaps in my NextJS project but it didn't change anyting: if I put the debugger instruction anywhere, when browser stops - there is no sources.
I added this to next.config.js

webpack: (config, { dev }) => {
    config.resolve.preferRelative = true
    if (dev) {
      config.devtool = 'source-map'
    }
    return config
  },