I've did a lot of digging and I learned that I need to use an OSS version of Heartbeat to achieve this. As such, I removed the version I had initially and installed an OSS version (initially 7.9.2, but also tried 7.7.0).
I'm still getting xpack related errors (the one below is from setup, but I get the same when I just run it)
401 Unauthorized: {"Message":"Your request: '/_xpack' is not allowed."}
Exiting: request checking for ILM availability failed: 401 Unauthorized: {"Message":"Your request: '/_xpack' is not allowed."}
Not sure how to continue with this, so any help would be appreciated.