There's a few good ones you can use to post blogs/articles on Nostr.

https://habla.news/ is the one I generally use.

https://primal.net/ now has long-form publishing, too.

https://yakihonne.com/ is preferred by others.

There's also https://highlighter.com/ https://untype.app/ and a new contender just released in alpha: https://www.longform.space/

All of them post long-form notes, which use markdown for formatting, and will be visible in any Nostr client that can display that note kind.

Better yet, if you want your own website to display your long-form notes, you can use https://npub.pro/ to generate your own blog site that uses Ghost templates and can even be attached to your own domain.

My site, https://www.nostr-reviews/ is entirely using Nostr long-form notes and npub.pro.