How can I fix Gboard hang after I use google dictation (long press on spacebar)?
Xcode has a visual profiler and debugger called instruments. Once you r device with your Mac, you might be able to snoop on the error logs, system calls and such. You will be at the mercy of however much symbols and logging google enables. 

Better might be to seek support from the vendor of the app if Xcode is either not an option or not helpful once you try it. 

N-2 iOS version support might be scant from google, but it’s only your time to try and get support from them.