It’s really a personal preference, but I do think that separating a podcast and blog usually feels more natural. My advice: if you are only going to post a couple episodes of the podcast very rarely, it’s fine to keep it all together as a single blog/podcast; but if you want the podcast to have its own name and regular episodes, separate it from the blog.
Micro.blog can handle both setups, because it uses a separate podcast.xml feed that only includes audio posts. And Micro.blog Premium can have up to 5 blogs/podcasts, so there’s no extra cost to keeping them separate.