If you can self host, wiki.js is easy to set up in a docker container. Mediawiki (What Wikipedia runs on) is pretty easy too.

If you have a small team, Obsidian and a syncing solution like git or obsidian sync might work.

I was able to work with my company’s it team to set up a wiki which is only accessible from within the network, including by vpn, and is hosted on a vps.