[edtechdev]

Logseq is free and open source https://logseq.com/ You have to sync yourself though (for now). You can also publish to github pages.

My only issues are: they are focusing more on the desktop and (now) mobile apps, instead of the web app. You can't quickly share items to the app or web version to quickly save links, etc. They did have github integration built into the web version but are abandoning that to work on their own paid sync solution that isn't out yet. But you can manually sync the files as I mentioned.

For now I'm mainly sticking with a wiki but keeping an eye on developments to logseq and similar open source apps like Athens Research, Bangle, etc. See this twitter list of different knowledge management tools: https://twitter.com/i/lists/1396562498002825240