Ask HN: Cross-posting content over multiple publishing platforms – Y/n?

I've been running a self-hosted blog with a newsletter (just a few people, nothing fancy) and I wonder - does cross-posting increase my visibility? Thing's I'd like to try are Substack, Medium and Dev.to. How does one deal with multiple newsletters - should I direct my subscribers to the original source (my blog) anyway, or better keep them posted at the platform where they have found the article? So, mind sharing your experience of cross-posting content?