How to redirect the main page with a slash to the main page without a slash?

Question

htaccess

How to implement 301 redirect in .htaccess from page example.com/to page example.com?

Wrote this code:

RewriteCond %{REQUEST_URI} !(.*/manager.*)
RewriteCond %{HTTP_HOST} (.*)
RewriteCond %{REQUEST_URI} /$ [NC]
RewriteRule ^(.*)(/)$ $1 [L,R=301]

It works for subcategories (removes slashes), but not for the main one.
What needs to be done to remove the slash for the main one?