I used a proxy to look up which servers the app was trying to talk to, looked up the cert from the server and which CA I needed. It was very arduous, especially when you installed a new app and just wanted to use it, e.g. for parking. This made me stop doing this. When giving talks to junior devs I used to explain that security and convenience are almost always on opposite sites and you need to figure out where between the two extremes you want to sit. In this case I opted for convenience.