I recently discovered that FreshRSS has a built-in xPath parser/webscrapper[1] so you can actually subscribe to any website, even if it doesn't have an actual feed.

It's not straightforward to use because of the lack of a test/debug interface, but its worth the effort to set it up!

[1]: https://freshrss.github.io/FreshRSS/en/users/11_website_scra...