iPhone 13mini display issue showing colored vertical bars

You may try some of these steps, please chack after each step....

1. Sometimes, a simple restart can resolve temporary software glitches. Turn off your iPhone, wait for a few seconds, and then turn it back on.
   1. Restart the device. That's it.
   2. Still not solved --> Force restart iPhone - Apple Support
2. If the issue persists, you can try resetting all settings on your iPhone. This will not erase your data but will reset all personalized settings to their default values. Go to Settings > General > Transfer & Reset > Reset > Reset All Settings and confirm the action. Note that you will need to reconfigure your settings afterward. All settings—including network settings, the keyboard dictionary, the Home screen layout, location settings, privacy settings, and Apple Pay cards—are removed or reset to their defaults. No data or media are deleted.
   1. Reset All Settings: Return iPhone settings to their defaults - Apple Support:- Return iPhone settings to their defaults
   2. You can return settings to their defaults without erasing your content.
   3. If you want to save your settings, back up your iPhone before returning them to their defaults. For example, if you’re trying to solve a problem but returning settings to their defaults doesn’t help, you might want to restore your previous settings from a backup.
3. Make sure you have the latest updates installed.
   1. Update Over-the-Air (OTA) —> Update your iPhone or iPad - Apple Support (IN)
   2. Update using iTunes/Finder —> Update your iPhone, iPad, or iPod touch - Apple Support (IN)

If none of the above steps resolve the issue, it is recommended to reach out to Apple Support or visit an authorized service center for further assistance. They can provide specific guidance based on your device model and iOS version.

If nothing helped...

Get a Genius Bar Reservation and Apple Support Options - Apple

Contact Genius Bar.

Manage Reservations - My Reservations - Apple

The best would be to...

Take your device to an Apple Retail Store or Apple Authorized Service Provider, or contact Apple Support:

Apple Repair and Repair Status Check - Official Apple Support

Apple Authorized Service Provider

Find Locations - Location Selector - Apple

Contact Apple for support and service - Apple Support 

This just happened to my sons iPhone 13 after updating to the 16.6. As soon as it turned back on it came up this way. We called Apple and they knew the issue but told us sorry we can’t help pay $279 and then we can help. They don’t care that the update is messing up phones. They won’t allow us to even add the apple care they said pay $279 to fix the bug issue or buy a new iPhone 14. They don’t care or want to help at all for something their own update did. The phone is perfectly fine he can use it just has this display quality issue. Seems Apple is declining on customer service. Senior advisor just said well it happens sometimes.