Pocket is a great app to save articles. Besides putting articles to read later, I also categorize the articles with tags in order to reference/ review them in the future. However, Pocket doesn't save the articles permanently unless you pay a huge amount annually. Meanwhile, Joplin's Web Clipper does a great job to convert web articles into markdown and save permanently. Thus I am thinking of migrating all my saved articles in Pocket to Joplin.
I know Pocket has API to retrieve all the articles' information I saved. Maybe the articles' url can be forwarded to the Web Clipper to clip the articles into Joplin
As long as the original site is still online and accessible then the articles are safe. Nowadays many website lock their articles into paywall, or the websites have already shut down so Pocket no longer have the access.
Wallabag seems able to save the articles forever. I may look into it as well.