How to formulate .htaccess 301 redirect (string insertion in URL)?

Question

htaccess

Woo Commerce for WP uses a specific rewrite base in its URLs For
example:
www.mysite.com/shop/product_cat/product_subcat/product
The Woo website explains that shop cannot be removed, as it can cause serious conflicts.
I need to migrate a site that keeps the results in the index, so I want to set up a 301 redirect in htacess like this:
All requests, except for a certain list (information pages, there are a limited number of them), redirect to identical requests, with an insert /shop/

The question is how to formulate a rule for .htaccess so that
www.mysite.com/product_cat/product_subcat/product
www.mysite.com /shop/ product_cat/product_subcat/product
/product_subcat is an optional part, it may or may not be in the link .

Thanks to

Answer 1

RewriteEngine on
RedirectMatch 301 /product_cat/(.*) /shop/product_cat/$1

Answer 2

RewriteCond %{REQUEST_URI} ^(.*)/dir1/(.*)$
# if string contains /dir1/
RewriteRule ^(.*)$ %1/dir2/%1 [R=301,L]
# Redirect all urls starting from dir1 to dir2 preserving further URL structure