https://heavy.com/entertainment/the-100-series-finale-review/
https://www.latimes.com/entertainment-arts/tv/story/2020-09-30/the-100-season-7-cw-finale
https://reactormag.com/the-100-series-finale-completely-misses-the-point-of-the-show/
https://ew.com/tv/the-100-series-finale-spoilers-jason-rothenberg/
https://www.eonline.com/news/1193768/the-100-series-finale-what-that-ending-really-means
E!: Do you have a vision of what transcending is actually like?
JR: No, not really. I think it's one of those unknowable, find-out-when-you-get-there answers, like what happens when you die. I think it's essentially like our consciousness is energy and our energy is joining what we call the Universal Consciousness, the higher level of consciousness that we all get access to if we pass the test, so what that means exactly is open to interpretation. Some people might take a religious perspective and others might say it's what religion, generally speaking, is based on, to explain that phenomenon.
https://www.denofgeek.com/tv/the-100-series-finale-ending-explained/
Does The 100 Have a Happy Ending?
You will have to decide this for yourself. On the one hand, it’s pretty dark that The 100 ends with most of the human race opting out of corporeal existence—like they have a choice and they decide that they’d rather be part of an alien hive mind than continue to be human. (Honestly, a very 2020 vibe.) While the Lexa-faced Judge tells Clarke that humanity has “added so much to us already,” for a show that depicted murder as a valid life choice more or less right up until the end, it’s not really clear what those qualities might be.
On the other hand, some humans do survive. They seemingly get a pristine Earth to live on, and they don’t have anyone left to fight besides one another. Still, for an episode that has a surface-level message of anti-tribalism, the final scene seems to hammer a different message home: a peaceful existence is possible when everyone but your family is dead.