I bet you could find a dozen or more websites summarizing your legal obligations if you wanted to create one web page.
Since the context was Facebook, I was speaking about what businesses should do. And especially large businesses. As far as I've heard, the EU isn't chasing folks who run a small website.
But they could, which has already had a chilling effect on small businesses. Even though the intent (and current enforcement) is to punish large companies, GDPR is written in a way that puts a large compliance burden on many small companies and startups.
Doing your accounting, paying taxes, and following labor laws are also burdens on small businesses. Not every small business is profitable enough to manage those things and that's ok.