I had done the best by following the code signing documentation, testing it locally and using transporter to verify the package
Can you clarify what you mean by "testing it locally"? I assume you are just running the app on your development machine. You should be testing in a pristine, "factory fresh" environment such as a virtual machine or, even better, a dedicated test device. These test environment must always be using the latest shipping version of macOS as that is what App Review is going to run.
And what is this "transporter" that you are talking about?
Just kidding! 😀 You are using some cross-platform app builder instead of Xcode, right? Well, you have to ask yourself. How much time and effort are you really saving?
To be honest, you don't need code-level support for this. Just build your app in Xcode and pretty much everything is done for you. Yes, I know! You are too far along to rewrite everything now. No money is worth more than money than you have already spent.
I suggest you contact whatever support resources exist for your 3rd party app-building tool. It will probably be another free forum environment like this one. But those people, unlike anyone here, will 1) know what tool you are using and 2) be familiar enough with it to offer you advice.