I'm also quite surprised there's no option for self hosting metadata on the free tier. To be fair, in my experience having managed metadata server for prefect (while they have similar Bring Your Own Server model) is quite hard to get right. But at the end we decided to keep maintaining it because our company prefer having all the data in our servers (including metadata).

But I'm still excited to try this, since at least now I could play around (and learn) with a partially kafka compatible system, without the burden of maintaining all of Kafka parts (and costs). Thanks!