How to lock Blog archive to premium patrons only?

Our dental blog WURZELSPITZE, dedicated to enodontics, has been in existence since 2008 and we have now published more than 3000 posts, amassing an enormous amount of knowledge and expertise. Until now, the blog was classified as private on Wordpress and therefore reserved for members who paid an annual fee. Now we want to make the blog accessible to all dental professionals who donate at least a small monthly amount. However, the 3000 legacy articles should be readable exclusively by our premium level patrons to prevent readers from logging in for a short time and little fee and then quitting. Is there a setting that classifies all existing 3000+ posts as premium level content ? Without having to manually set this for each of the 3000 posts ?
Thanks in advance for any advice . I am very grateful for the all the help !

Kind regards

Ha-Wi

You could easily lock those posts using the WP plugin.

It would be needed to be done one by one or through the database with the free plugin.

However if you get Patron Pro (a premium addon for the plugin), you can lock posts based on post type, category, tag or custom taxonomy.

So, if those posts have any specific tag that is only for those posts (ie, premium, member-only or whatever tag that would distinguish them from all other posts), then you can just get Patron Pro and lock all posts of that tag, category or post type by using its advanced locking options in plugin settings.