That looks great! I ran into a couple of feed generators when I first needed this myself, but they were either paid or clumsy to use. That's when I thought, "alright, I can build this myself, and then I can even use CSS selectors, since I'm comfortable with those anyway". Of course, that is the point I should've thought about explicitly searching for one that supported that :)
Ah well. What I do like about my current approach is that I have full control without having to run my own server, which is nice.
The biggest issue I've found is people struggling to work out which CSS selectors to use. I wrote a blog post not that long ago to help people use the browser's developer tools to do that. Might help too with anyone trying to use this (although perhaps most of the HN audience doesn't need help here): https://www.fivefilters.org/2021/how-to-turn-a-webpage-into-...
Ah well. What I do like about my current approach is that I have full control without having to run my own server, which is nice.