Need RSS feed fixed so it crawls Feature Image - Wordpress Blog

I need my RSS feed to be fixed in a way that it crawls the feature image of each blog post as opposed to the first image within the blog post.

I know it's not a difficult thing to do and merely requires a Code to be inserted or changed. I don't want an additional plug-in as I have enough already.

I need this for Triberr & Bloglovin and would need you to do necessary adjustments to Triberr & Bloglovin in order to reflect the changes - if necessary.