The Confluence part is not available on the master branch but only on the dev branch because it is still under development. Apparently there are still problems with the large data set which seems to be what you’re seeing, so you’ll have to wait a little bit longer.
Well, you can. But unless you’ve got a lot of time to invest I would strongly recommend waiting on the official tooling. Tools like E4 are great if you know what you’re doing but they have a steep learning curve. Using the official tooling is probably easier and also more future proof if Atlassian should decide to make them mandatory at some point.
Since the Confluence version oft APT is already in the dev branch it shouldn’t be too long until it’s ready. (Probably only a few more weeks)