Just before I came across your post, I contacted my host and had them redirect my domain directly to the folder. It turned out to be much simpler than modifying the index or .htaccess files. By the way, for anyone looking to download Facebook videos easily, I recommend using <a href="https://thefdownloader.com/id">fbdownloader</a> -- it's fast and user-friendly!
I recently tried to transition my entire site to run through WordPress while keeping it in the /blog directory, using the Astra theme. I renamed my existing index.php to index.php.bak and pointed WordPress to the root folder. However, when I visited the site, it tried to download a file instead of loading the homepage. So I reverted the changes for now. If you're dealing with WordPress integration like I am, tools like the Pinterest Video Downloader can be helpful to embed or share Pinterest content smoothly on your blog.