Double posting on the same website URL issue

I cannot change the permalink on the site. It has to be the way it is.

Otherwise, I will have to replace my websites with another WP theme.

Do you actually want both of these very similar posts to show here?
https://www.screencast.com/t/dam4TzzLp
https://www.screencast.com/t/E4TXVuM041CD

If so you would need to manually edit the slug by adding. For example, add -2 to the end of one of them.

Or else setting the older one to Draft should also work.

It won't help me.

I will have to find another solution.

I'm sorry about that - it's very unusual to have duplicated slugs.

Yes, I Will Go with another theme.

You could also try the Convert to Blocks option. I believe that will also fix the issue.

I already have tried this.

Thank you for taking your time to look into the issue.