I found a workaround by using https://siftrss.com/
In the URL field, enter the generic RPS RSS feed (linked by Grizzly above).
Wait a second for it to load and then use the filters to recreate your pre-redesign feeds.
To get Nate Crowley’s articles, for example, include items where dc:creator is Nate Crowley. You end up with a link that you can subscribe to in your RSS reader, e.g.: https://siftrss.com/f/BMWZYbkRxz
If you use it, please consider supporting the creator via the “Buy me a coffee” button!