For a wiki farm like Miraheze, GDPR/CCPA/etc compliance is fairly easy. MediaWiki collects fairly little personal data about users, and there are well-defined methods for the site operator to export or delete that data if a user requests that they do so.
Besides, that all kicked in years ago. It's not a new concern.
Cookies were regulated by the ePrivacy directive back in 2009. The case raised above is about someone who had access to see the users' IP address. Handling training and authorisations for people with access to personal data is an ongoing job, not something you do once and forget.
Once sites are planned with it in mind from the get go it's really no big deal, and huge for the end user.