how to rewrite attachment permalinks

So I am already using pretty permalinks. However my attachment url looks like this: https://domain.com/%category%/%subcategory%/%post%/attachment/%attachment_url%/

I’m trying to remove the “attachment” directory. I’ve only found a similar function that works for people without pretty permalinks already activated. I tried modifying it to remove the directory and it didn’t do anything.

How do you remove the “attachment” directory?

https://wordpress.stackexchange.com/questions/14924/pretty-urls-or-permalinks-for-attachments