You can send with calibre-web to kindle if you have an amazon account. You get a specific address for your kindle. They appear under documents in your library, legal or otherwise.
I created a libreddit instance for myself, so if I want to browse a specific subreddit that hasn't moved away, (e.g. /r/warthunder) I can without using the official site.
You can use calibre-web to send to your Kindle email. They will appear in the Kindle as "Documents"