Why wordpress multisite root site showing blog prefix by force?

Got a solution at – https://isabelcastillo.com/remove-blog-slug-multisite

In the root site of my directory base multisite, I went to Settings -> Permalinks.

Then I change my permalink.

Then go the Network Admin -> Sites -> and clicked on Edit

Then switched to Settings tab -> Now remove the blog text from Permalink Structure and saved.

This is not recommended. If you do this on the main site of your network, you must make sure that none of your posts, categories, or tags have a slug equal to the slug of a subsite. That would cause a conflict.