Confluence, compared with the other Atlassian products, was incredibly slow for me also, when started with the atlas commands. Which helped a bit, is starting with
atlas-run --server localhost. This way you bypass all the networking effort, like DNS resolution, routing and things like that. That is, what @steve.behnke mentioned.
In addition, you can try to give Confluence and the JVM more memory, and see if this results in better performance.