Unable to Modify Link Text

You haven’t disabled it, one of those screenshots is taken on an older version of WordPress and the block editor that didn’t have a link text box.

Look at the toolbar and you’ll see the icons for the link in the toolbar are not the same.

Additionally, you don’t need the link text box to change the link text. The text is directly editable:

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Click on the text and start typing/deleting, or use the arrow keys to navigate to it the same way you would do it in any word processor or notepad application. The popup box with the link text box is there purely to make things easier, it’s not the only way to change it or even the preferred method.

If you need that particular specific method though, upgrade WordPress.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)