Clock widget on iOS 26 Home Screen can't be edited on iPhone 12 Pro Max

These are the clock widget options that you have on iOS 26

On iOS, once you have selected a Clock widget, you can change the country or city that the widget displays. However, the widget type itself cannot be converted into a different style—for example, you cannot directly switch a regular Clock widget into a World Clock widget. If you want to use a different type of clock widget, you will need to remove the existing one and then add the new widget of your choice.

Suggestions and Feedback for improvements --> Apple Inc says; "We read all feedback carefully, but we are unable to respond to each submission individually."

1. Here is how for iPhone · Country or region* Select your country or region. · Feedback Type* Select feedback type. · Comments* Enter a comment.
2. Feedback - iPhone - Apple

To improve my understanding of the phenomenon, it would be highly beneficial if you could share a full screenshot (Do not crop it). Visual representations carry a greater impact than written descriptions.

Please remember that this is a public forum, so when attaching a screenshot, please avoid including any personal credentials such as IP addresses, card details, email IDs, Apple IDs, IMEI numbers, serial numbers, phone numbers, order IDs, or any identifiable location information if you are sharing a map.

With the limited information that you have provided, It is hard to even guess the problems faced by you. 

You may get faster and better responses to your query by --> Writing an effective Apple Support Commun… - Apple ...

Please re-post with detail so that someone else can help.