I have inherited a project that is stuck on webpack 4 / angular 11 / lerna bootstrap that I am trying to upgrade to webpack 5 / workspaces etc. and it's like a Rubix cube (or Lament Configuration), so please don't tell me some utopian advice like "just use angular-cli". It's not that simple.
Anyway, when I did try to use @ngtools/webpack or packagr I noticed that there are hundreds of typescript errors in my Angular HTML templates for things like unknown references. These haven't broken the app and have not been reported during our bespoke webpack4 build that uses html-loader, ts-loader, ForkTsCheckerWebpackPlugin and ttypescript (for paths).
How do I configure a loader or plugin to report typescript errors in Angular HTML templates?