Anyway, if you think Confluence is complex, that just means you haven't tried it yet, or you spent too long looking at the admin panel options. Cars are complicated if you start doing gearbox changes, but if you're just sat driving then it's a piece of cake.
I tried tons of software for this before I settled on Confluence, tbh nothing came close.
https://www.wikimatrix.org/compare/BrainKeeper%2BCentralDesk...
Use the wizard to narrow down choices.
These options look like the highlights to me:
Zoho Wiki: https://www.zoho.eu/wiki/pricing.html
It's clean and fully featured and, for the price, might be just what you're looking for.
Also, two alternatives that I wanted to test but never had the time to:
For a group without a budget, I'd lean more towards Dokuwiki or Mediawiki, both of which are still fairly easy to administer and feature-rich.