Why would it be impossible? Twitter for years has allowed people to mark content, including their whole account, with a content warning. Current categories are:

Why would it be impossible? Twitter for years has allowed people to mark content, including their whole account, with a content warning. Current categories are: Nudity, Violence, Sensitive That puts most of the burden on the poster, and checking the occasional box is not much of a burden. And these days it also acts as a great tagging system for automated ML filters. Combine that with good tools for users to report violations, and the burden seems pretty manageable. And honestly, it might lower site burdens. If people only see what they want to see, it could reduce user friction and incoming reports.