Here are a few examples of such products, Https://spreadtheworld.net/ And Https://newsletteros.com/. - Source: dev.to / almost 3 years ago

Janel Loi's authority putting NewsletterOS and PodcastOS together with No-Code tools informs her new job at On Deck, where she will meet more creators to serve, and also serve them better because she has her ongoing side projects. - Source: dev.to / over 3 years ago

Listmonk is fantastic -- I use it for the newsletter of my own blog and am amazed by how simple it was to set up and how easy it is to operate and use every time I send out a newsletter. Prior to Listmonk I used Mailtrain[0] and like Listmonk so much I want to run it as a service (with 30% donated back to the Listmonk project of course) -- deliverability worries and initial setup aside it's just the kind of... - Source: Hacker News / almost 3 years ago

Never tried but have a look at Mosaico and GrapesJS. Both are open-sourced and used by Mailtrain. Source: over 3 years ago