It sounds exactly like what the OP is looking for. In addition to being a easy-to-use (micro)blogger-focused platform (no ads, $5/month basic plan for hosting), the fact that they allow you to host everything on your own domain and cross post to more widely used platforms like Twitter and Medium seems like the best of both worlds. My current flow is writing in iA Writer and saving to Dropbox (for long term archiving). iA Writer allows publishing directly to micro.blog. Following other people through RSS feels like a breath of fresh air after being used to the Twitter feed for too long. I thought that RSS was dead for a long time, but checking out NetNewsWire and the default feeds there restored a bit of faith for me.
I hope and believe that blogging is going to survive this current centralized social media boom, and come out stronger in the end.