I started accumulating Substack newsletters in my email box, some going unread.
Just moved all my newsletter subscriptions to RSS Subscriptions in NetNewsWire.
It turns out that each Substack newsletter has a feed url:
https://your.substack.com/feed
If your Substack has a custom domain your feed URL would be:
http://newsletter.deverman.org/feed
– FAQ on Substack
– Original Twitter Thread