The comment you mentioned is that The Elementor team hasn’t built the solution for AMP, but it does not mean AMP team cannot built for elementor.
Please don’t worry about that, it’s just that they have not built anything for amp.
Also regarding the issues, as you are very aware elementor has very vast functionality and due to it there must be some issue. But please be assured our team will help you it and make sure your issue gets resolved.
Thank you very much for purchasing the extension and I assure you that you did not wasted your money.
We are always here for your help.