I have a client that changed jobs. He wants to redirect all pages on the wordpress site to a specific page on that site. But he also wants to keep all the SEO from the blog posts. So I need all the blog posts to show up, but redirect any old pages to the new page. So, for example:

oldpage.com > oldpage.com/specificpage

so anything that is not a blog post goes to oldpage.com/specificpage

the blogpost would go to blogpost

I am able to redirect everything to oldpage.com/specificpage

I have excluded the homepage and /wp-admin/ etc.

But there are over 4,000 posts and to redirect each one individually is impractical
Is there a way to redirect everything except the posts through .htaccess?