Remove Duplicate Identical Slugs in URL

I am currently sitting with a blog url that looks like this: https://www.thedomain.com/blog/blog/blog-post — sitting in the root folder (it is WordPress)

I want to be able to remove one blog in the url. I tried adding this in my .htaccess folder but I get an error: The page isn’t redirecting properly

RewriteRule ^blog/(.+)$ https://www.thedomain.com/blog/$1 [R=301,L]