I've been considering trying to get to a similar result, but considering making my actual blog _be_ a (minimal) ActivityPub sever with a si gle user/actor such that posting to the blog is publishing an ActivityPub post, and have replies to that post coming directly into the blogs own inbox, then show up as comments. Anyone else weighed up the two approaches, I'm still on the fence tbh.
However since I'm not a very good frontend dev, posting to this is currently done through a CLI application without great UX. :D If you're interested, I would *love* to collaborate with someone on it.
PS. a running instance where I post now and then is https://marius.federated.id