How to test a game on iOS?

Question

iOS

Share your experience of testing mobile applications on iOS
Now I'm testing the application like this: the developer throws off the .ipa, I install it on the test device. Before that, I create a test account in the iTunes Connect sandbox. I open the application, check that ADS is displayed where necessary, I buy ads disabling from the application (from the application, the axis allows you to log into the iTunes test account). Quite a long process, I want to optimize it.
I know that TestFlight is often used for testing, but according to the tutorials, the preliminary setup to make everything work looks complicated.