It doesn't matter if Digger is good or bad. The point is that it is capital-T True.
Kenny's speech about how it doesn't matter if the play is real or fake or funny or tragic is a meta-commentary on the entire film. It doesn't matter if it is good or bad, or funny or sad, or satire or meta-satire, or anything at all. The point of the film is to speak honestly to this moment, just like Digger does in his monologue to the EU chamber. We are far past the point of no return with climate change and our continued extraction and consumption of oil and gas. We are beyond the point of Don't Look Up. The point of this kind of art is to show us the reality of our collective situation. That doesn't mean we should give up, just that it is important to be honest about reality.