I’m an Android guy, but I am not a cheerleader when it comes to choice. You can’t go wrong either way. You just have to research a little and determine what is most important to you and which phone excels at it.
Does the trolling bible need internet or data access? If not, why can’t you continue to use it for the app? I still have my original Android phone and I use it for testing.
If you are serious about an Android, do your do diligence. Identify what is important like say battery life. Then get on the internet and check out reviews for the latest phones. See if there are issues with what is important to you. And absolutely seek out the newest phones, since like a computer, your phone hardware will be able to handle new OS updates for as long as possible.