wat
It would probably be better to publish the newsletter as a "long-form content" event using https://habla.news or https://highlighter.com. I prefer Habla because of it's UX and design (I've only published two minor long form posts though).
Discussion
Nostr has a specification for posting long-form content such as blog posts, articles and newsletters (this is called NIP-23). This type of post contains a bit more metadata and lets you edit the content after it's published (compared to your normal posts/tweets which is not editable after they're published). Habla and Highlighter are just frontend services for posting such posts on nostr.
Maybe this FAQ can help you better understand this