The wiki format has indeed become ubiquitous for fan sites, but many fan wikis are fairly elaborate and ad-free (-ish, at least). Often the case for popular gacha games at least, e.g. https://bluearchive.wiki/.

The problem is that Fand*m makes finding results from the decent wikis unreasonably hard, I end up having to use extensions like https://getindie.wiki/.

Also, Discord all but killed the concept of a video game fan site...