If it’s not programmer error, then there’s some simple things you can do to speed up your app. I would focus on two things; 1. reducing DOM rewrites, and 2. limit the # of watchers associated to Angular ng attributes.
For 1. try to minimize adding/removing elements to/from the DOM. There are a number of tricks here, I’d recommend you do a little research. For 2. check out bindonce (https://github.com/Pasvaz/bindonce). These two items are related, solving for 1 will generally help with 2.
However, I think longer term, integrating Angular with something like reactjs makes a lot of sense. Angularjs rerenders the entire DOM when an element is manipulated, which, if you have a lot of DOM elements, really slows down your application.