single post templates and post categories

Hello,

I need help regarding single post templates.

I created 4 different single-post templates

In each single post template, I implemented the post category (There are 1-4 single post templates and 1-4 main post categories (1 category is for one single post template)

Even though I did everything according to the instructions, when I create a new post through a let's say template 1 and select main category 1, and then create some more posts through other single post templates and assign them other categories, in the background (through the be builder) I see changes, but on the preview page I don't. It's always, for example, the same category number 1 showing.

I need immediate help regarding this problem, or a different suggestion for the implementation I need, if the theme doesn't allow it (why are these options available if not possible).

I really appreciate any help you can provide.

All the best,

P.S. Last time I waited for your help and support for more than 24 hours. Please be kind and respond within 24 hours.