The Kurzgesagt videos on these sorts of topics are interesting and entertaining, but they're often very speculative — they can rely heavily on unique but unproven theories, unprovable philosophical questions, or even just interesting sci-fi premises.

They're definitely informative and interesting within a given scope of discussion — it's good to ask interesting questions and explore what different answers might look like, because it helps us to push the boundaries of our mental models of the universe. But some of the videos — particularly the ones on Boltzmann brains or solutions to the Fermi paradox — are a lot closer to "here's an interesting thought experiment" than "here's something that's likely to be the case in our universe".

(Although they're usually very explicit when they do dive into this sort of speculative territory, and they also do a lot of videos which aren't in this vein at all — this is no slight on Kurzgesagt and the people who enjoy watching them!)