I self-host an instance of https://feedafever.com/ which works nicely with https://www.reeder.ch/ on my iPhone and Mac at home and also quite nicely online (at work, but psst, don't tell anyone).

Fever is unsupported, though [1], but it's still working nicely. Once it stops working, I'll switch to something that's supported by Reeder, which is an indispensable piece of software for me.

[1]: https://shauninman.com/archive/2016/12/24/goodbye_mint_goodb...