Is that really about Twitter sharing ad revenue? The page is just talking about paid "subscriptions" to Twitter creators. That seems like a business model where the revenue cut is irrelevant. Nobody will pay $5/month to subscribe to one person's tweets.
Yes the FAQ sucks but it's the same deal as TikTok/Youtube/etc: you get a 80% of revenue made from ads that appear on your content.
https://www.reuters.com/technology/twitter-share-ad-revenue-...
It apparently hasn't fully rolled out yet so the docs are confusing. They claimed it has started on Feb for Blue subscribers but that may change.
https://help.twitter.com/en/using-twitter/creator-dashboard
Still it will be interesting to see how many hundreds/thousands of mom & pop careers will be built off Twitter now.