FYI, Tumblr does support RSS via `/rss` at the end of any Tumblr (e.g. https://micro.kraft.blog/rss ). Blogger too ( http://wpisbetter.blogspot.com/feeds/posts/default ).

Medium also supports RSS for sites based on Medium, e.g. https://blog.coinbase.com/feed , but not for Topics as far as I can tell.