First thing I want to point out is that lemmy can kinda fill this niche (see the docs on this). Start a community and turn on “moderator posts only” (such that only the moderator(s) can post) and you’ve got a basic blog with post comments across the fediverse built in (for which you’re the moderator). It will have RSS built in too, and a hefty character-limit per post of 50,000 (last I checked) which is ~10,000 words per post, along with markdown formatting. And if you want complete control, you could run your own instance through a service like spacehost.
Beyond that there are other more dedicated platforms.