Keyword cannibalization and how to fix it

At the start of November I published a blog post that had similar title as the product that I sell, the blog post was like ultimate guide on plugin features and how to use them, but just now I figured out that slug was /referral-program-refer-a-friend-for-woocommerce-premium/ while my product slug is /refer-a-friend-for-woocommerce-premium/ Title of blog post is: Creating a Referral Program with Refer a Friend for WooCommerce PREMIUM Product title is: Refer a Friend for WooCommerce PREMIUM. 15/20days from publishing blog post, my page dropped from top 3 position for 2 main keywords, no other change was done on the site and I was pretty much same position for 2 years. I suspect on keyword cannialization. What is the best course of action here? I wanted just to do 301 to product page and create new blog post from this article but change content, so that would not have mentions to my plugin title except link to it. But AI suggested that I 301 to new blog post. What would you suggest? Thanks!