Issue with permalinks

[Title moderated, in future please use a more descriptive title]

Because of having no idea about connecting which department, I prefer to write you here directly.
Let me explain this in an axample:
Figure out I have an “about” page and its url: “https://mehmetalimersin.com.tr/hakkimda“. And after a while I forgot “hakkimda” page and I try to create a “hakkimda” post.
If you choose your permalink as post name the post that you create as “hakkimda” will occur as “https://mehmetalimersin.com.tr/hakkimda” too.
I dont know what the solution but as we know if you create 2 post with same name the second ones permalink has “-2” For example ../hakkimda-2.
As I wordpress user I want to make you know. PS: Now I have these two post(page and post).
If you take a look in menu bar about page goes to post type, the other goes to page type!

Best Regards

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