Earlier quoted context omitted.
GitLab pretty much covers BitBucket (code), most of Bamboo (GitLab CI), maybe Jira if you use it only as a basic issue manager (forget about Agile stuff). Confluence is probably the hardest one. You could use any wiki software but the new "live-editing" stuff (Google Docs style) is pretty good for productivity. Hard to find an on-prem equivalent. Confluence's integration with Jira is hard to compare too.
What agile stuff are you missing from the paid versions of GitLab? We have epics, roadmaps, milestones, and iterations. The only thing that is missing I can think of is workflow enforcement, but that doesn’t strike me as Agile.
I always go the impression that GitLab was doing excellent in code related workloads but sub-par in issue and test record tracking.