That could be a start, but I think you might need the log files. The easiest way to get them is to go to your configuration folder (the folder where all your configuration files are stored like configuration.yaml and ui-lovelace.yaml).
There is a file there that is named
home-assistant.log all errors will be logged here. I think it gets reset after each restart to keep it clean, but I never had to use the logs before as most of the time I have the console open anyways.
But the way you say it, there might be no logs on this if the app isn’t able to do anything at all. Could you maybe send screenshots of every screen you see from scratch? It might also be good to know which device you are using and what version of iOS you are running.
I am not really good with iOS apps, so I can’t tell you much about it, but all these little details might help give me (and anybody that reads this) a clearer image of what is going on.
One thing I do know is that iOS has it’s weird stuff as well and sometimes things won’t work for no obvious reason. Crazy thing is that some of these things can be fixed by restoring the iPhone with a fresh version of the latest iOS, it sounds silly, but it really helped my out many times in the past. If you store your photos on iCloud or another external source I’d suggest setting the iPhone up as new (without the backup) and pull the contacts (and other important data) from iCloud.
I know it is a big pain in the backside to do something like this, especially if you hold a lot of data on your device. But even so, if you have used the same backup for years, it would be a good idea to do this. I know people that still use the same setup as they had on their iphone 4, so they copied their old stuff to the new over and over again.
Oh, btw do you have any other iDevice like an ipad (that can run iOS 12) or another iphone maybe?