/blog/tegory%/%postname%/ = broken posts

/blog/%category%/%postname%/ = broken posts

I want my website structure to look something like this.

My website is https://allthingsmin.com
my blog is https://allthingsmin.com/blog
then I have a few categories in my blog e.g. “creator academy” / “entertainment”
and an example post I have posted is “develop-your-branding”

I want my post URL to look like this
https://allthingsmin.com/blog/creator-academy/develop-your-branding

without making any changes it looks like this
https://allthingsmin.com/develop-your-branding

I tried changing permalink structure to
/blog/%category%/%postname%/

which lead to my posts being inaccessible.
error: This page doesn’t seem to exist.
It looks like the link pointing here was faulty. Maybe try searching?

Can you please help me fix this?
explain how to do it, please.
or refer to some video tutorial, if that’s also an option as well.

thank you.