Is it doing anything novel? What functionality does it do above and beyond CRUD? If the answer is no, pick a common MVC framework like Django or Rails or Adoni

Is it doing anything novel? What functionality does it do above and beyond CRUD? If the answer is no, pick a common MVC framework like Django or Rails or Adonis, generate the models from a copy of your database, and make a minimal proof of concept. This will go a lot longer way than just complaining about how bad everything is, and how everything needs a rewrite.