WordPress Migration Post Problems

I am currently working on a website, created with WordPress, the website has been compromised with security flaws, because when WordPress was installed they did it with a version of PHP 5.2, also the website is working with WordPress version 5.3.4.

I am looking to make a clean copy of the website, first to be able to install the latest version of PHP to date 7.4, since the website generates errors when I try to change the version of PHP by force.

I am looking to make a copy of the post, with their respective featured images, using the WordPress exporter I have managed to export the entries without a problem, but I cannot export the featured image.

I have tried to export the entries, and then manually upload the images to the uploads folder. It has not worked.

I don’t want to migrate the entire site as the template has some styling errors that need to be fixed.

There is a way to migrate blog posts with the featured image, but I haven’t figured it out so far, can you give me a hand? Maybe a plugin? Or how can I copy the posts directly to the database from phpMyAdmin, any suggestions?