Suppose you want a really long lived store for your plain text or html files (archive.org is unlikely to go away anytime soon)
1) create an account on archive.org
2) upload your folders of files as an Archive.org item
(works best if you upload with a root folder included so that the archive.org meta files get created outside of your first level documents folder)
Your index listing will live under a url like:
https://archive.org/download/test_blog_2020/test/
(or even sub-folders like: https://archive.org/download/test_blog_2020/test/blog/)
(note that "test_blog_2020" here is a global unique identifier you can customize when you first upload to archive.org. as long as it is available of course)
Each file will have its own url like: https://ia601506.us.archive.org/4/items/test_blog_2020/test/...
(which means you can use relative links in your html and they will just work)
And you can use the "Edit" functionality to add more files to your folders:
via a url like this: https://archive.org/edit.php?edit-files=1&identifier=test_bl...