Just in case you weren't aware, uMatrix has been deprecated and will receive no further development, including fixes. It still runs fine now, but it may not in the future.

Blocking domains works right now but what if Facebook register a new domain? Or a thousand new domains? Or they proxy traffic through a site owner's domain? What's needed is a way to block Facebook's privacy invasion regardless of the tech they use. That is unlikely to be a problem solved by tech. It needs enough people, including governments, to tell Facebook they're unhappy with Facebook's activity.