Thanks so much for sharing how you accomplish this and which plugin you use for memberships. I'm not yet ready to implement a paid newsletter, but I wanted to make sure it was "do-able" before I got too far along in setting up The Newsletter Plugin.
Yes, I looked at briefly at Substack and spent quite some time researching Ghost. The latter is more full-featured than Substack. Unfortunately, it doesn't have a way to automate newsletters, otherwise I might have gone that route. So, I'll be sticking with WordPress.