While I detest Jira, I find Confluence to be quite good for writing documentation. It's full featured and mostly just works. For our customer facing documentation at work we use Zendesk and while it's good it's nowhere near as good as Confluence.
We're having this struggle right now trying to replace Confluence thanks to Atlassian's "no more Server licenses" foot-gun. The other wiki software that's out there just hasn't impressed me so far. This one is painful to set up and keep running, that one is awful to edit anything in (especially if you're non-technical), most of them don't support collaborative editing or inclusion of Office doc content on pages, and that's before the fun places where we've integrated Jira and Confluence to make workflows easier. I keep hoping to find something under a rock that really wows me (or that one of the existing competitors will really step their game up to pick up the people exiting Atlassian).
The fact that collaborative document preparation is as troublesome as this in 2022 is a damning indictment on the computer industry. (It's become very good at advertising though.)
It really is puzzling to me that there aren't more and better options in this space. On the one side of the fence you have things like SharePoint or some of the Google bits that are fine for synchronous collaboration on a page or document through a browser, but not very tech or API-friendly. On the other side of the fence you have things like Mediawiki and Dokuwiki that are super tech-friendly, but very manager-unfriendly and not particularly good for synchronous collaboration either.
It surprises me that Confluence continues to be the only thing sitting in the middle of those, and while some competitors have started to shyly emerge (Bookstack, xWiki, I think there's one in progress at Jetbrains), nothing feels like it's really aggressively going after the Confluence market-space directly. Given how many people I've seen comment that they're not fond of Confluence but can't seem to replace it (at least, not until Atlassian forced their hand with the server-license fiasco), it seems like a natural space for people to pursue.
> I keep hoping to find something under a rock that really wows me
Send me an email at Paul at dokkument.com and that's exactly what we are working on. Yeah unforturnely you will not see anything interesting on our landing page