Custom slug? Delete /categories/ from URL?

hey people… well here is the thing.
I have pages on / , a custom post type named works on /works/ and I have posts going for /blog/ (blog is a category, this way i don’t mess with pages and the custom post types). Inside the blog, whenever i click a category (all of new categories are child of the blog one), it goes /categories/blog/name_category so i’ve included this on my functions: https://pastebin.com/wsVztq3s this way that categories goes away. But this brings me a problem… My /works/ custom post types permalinks give me 404… can anyone help me change this?

You may check the blog with the /categories/ at https://www.sendoushi.com/blog being the root of the website for works and pages https://www.sendoushi.com