contacts crash and flash immediately, iPhone 8 iOS 13.3

[Sumleilmus]

Today, starting while at an Apple Store, every time I try to open the Contacts app) on the phone, the screen flashes white, and the app does not open. I backed up the phone to my desktop computer and to iCloud

It is not fixed by (I might not be calling some of these by their right names):

quitting all apps
respring (volume up, volume down, hold down side button)
complete power cycle (power the phone completely off, power it back up)

Is the next step to "restore" from within iTunes on a desktop computer to which the phone is connected by cable?

If that does not work do I head for DFU mode and restore from there?

At what point do I set it up as a new iPhone, and restore from backup (which might be a restatement of a step named above)?

Thanks in advance for any help. Search has not helped me, here or WAN.

 

[Sumleilmus]

I turned off Find My iPhone, then chose "restore" from within iTunes on my desktop computer to which the phone is connected by cable. This did not help.

I would appreciate some guidance from someone more experienced.

 

[Sumleilmus]

This problem started after I made a change in one entry in Contacts. Multiple resets of the iPhone and deletions of all data, followed by restoration (sometimes from local backups, sometimes from iCloud) did not solve it.

I was able to reset, delete all data, restore, but not migrate any of my own personal info into the phone and determine that in that case, the Contacts app would actually open as usual, but lacked any entries.

I wonder if this can be solved by restoring everything except Contacts data, and then restoring Contacts data from an iPad backup, since the iPad's contacts app works very well indeed. I don't seem to be able to control any of the more granular details of the restore, and, because of the multiple resets, I now can't "see" any iPhone backups to my local computer from before the beginning of the problem. I suspect but can't prove there are older backups that have not yet been trashed.

Any suggestions? The people at AppleCare were not able to offer any useful advice save for directing me to the "Genius Bar." a place I have seldom frequented since beginning to participate in forums such as this one long ago.