I have migrated all my content from my old custom blog, https://www.chrisdeluca.me, to micro.blog, chrisd.micro.blog (I haven’t switched the domain yet).
I disabled the RSS feeds in micro.blog, and I can post, but they do not show up in my feed (or any one else’s, seems like).
Micro.blog uses the feeds under Account → “Edit Sources & Cross-posting” to control what posts show up in the timeline. To update it, you can add your blog feed back by adding this URL on that page: https://chrisd.micro.blog/feed.json
Then when you post to your blog, it goes to your blog and the feed, and then from there to the timeline and followers.