It's interesting to continue to see variations of these topics come up at different places. This looks to be the Gen Z incarnation of an old article I came across about 8 years ago on the topic:
https://danielmiessler.com/p/difference-existentialism-nihilism-absurdism/, the Gen Z version being complete with a random YouTuber talking about the topic in the fashionable YouTube style and in an ad-hoc way amidst an onslaught of tangentially-related graphics and background music - the video itself exemplifying absurdism by being an abdsurd YouTube video.
My present thoughts on the existentialist/nihilist/absurdist complex is that, firstly, well... I will begin with nihilism, as it is the most obviously problematic. Nihilism says that there is no intrinsic meaning to anything and it's pointless to try to do anything about it. The "and" part is important because one can feel that there is no intrinsic meaning to anything, and this is a perfectly valid feeling or mind-state. The unnecessary part is the "and," as this is a value-judgement of the feeling or mind-state. Feeling that there is no intrinsic meaning to anything, or being in such a mind-state, is just that. One need not add anything else to it. Hopefully it is now clear the problem with nihilism.
Next, we move on to existentialism. Existentialism says that we can make our own meaning. I never really bought this idea because it always felt intuitively wrong for some reason. On closer inspection, it becomes clear why. Existentialism is actually just the modern incarnation of the ancient concept of hope. So, in ancient times, hope was seen by the Stoics as a negative thing to have (despite popular opinion to the contrary) because on the flip-side of hope is fear, and there were many tales about such hopes going wrong. In the later centuries, hope was rechanneled into the concepts of "hope in Christ" and "fear of God." In the modern era, hope has taken the form of existentialism. So, where are the two sides of the hope coin now? As HealthyGamerGG once said in one of his YouTube videos, hope is something like standing in the present and looking towards the future. I think this describes existentialism. One is present to what is going on, while also looking towards the future - but why? The reason why, I think, can be explained only by a complex interaction of societal forces, which may be highly individualistic. Basically, one way or another, the normative ethical culturally relative society is where the hope, fear, and, ultimately, existentialism, come from. So, while it may have its uses from time-to-time, existentialism cannot possibly stand on its own as a core philosophy.
Finally, we have absurdism, which establishes that, like nihilism, says that there is no intrinsic meaning, yet unlike nihilism recognizes the validity of the search for meaning. This is probably the hardest philosophy of the three to see through because it seems to be reasonable, in that the ultimate conclusion is to just go on living. But let's take a closer look: So, the philosophy says that there is no intrinsic meaning. This isn't actually nihilism, but rather an acknowledgement of the feeling or mind-state of nihilism - without the "and" part. Looking at the website definitino of absurdism, we see that the search for meaning is then defined as a process. So, what is in conflict with each other? - the intrinisic meaninglessness of life and the process of searchin for meaning. There may be some intellectualization going on here in the person who is applying this philosophy, but ignoring that possibility, the conclusion is to simultaneously accept this dichotomy as well as rebel against the dichotomy. So, this is actually quite an advanced way of viewing things because one has to first assent that there is no intrinsic meaning, then they have to avoid the pitfall of despair, then they have to acknowledge their drive for meaning and hold that against the assented-to intrinsic lack of meaning. The tension is addressed not by mere acceptance of the conflict (which would end in resolution while holding the aforementioned dichotomy) but by adding the tension of also rebelling against the conflict. So, now there is a tension within a tension in the mind of the absurdist - one between the intrinsic lack of meaning and their drive for meaning, and the second being between the acceptance of this tension and rebellion against it, with the ultimate result being an embracing of what life has to offer. With all of this tension in the absurdist philosophy, it likely acts as a spur to provide one the energy to be able to live in the present.
While quite fascinating how it appears to achieve a meditative or perhaps zen state of mind, I would say the philosophy doesn't stand for two reasons: 1) the initial premise was assented to, rather than simply acknowledged, effectively creating an "and" and value-judgement to the initial feeling or mind-state that life has no intrinsic meaning, and 2) Reasoning simply, if one can hold 1 or 2 dichotomies in their mind in order to achieve mindfulness, why not 3, 4, 5... ad. infinitum? Why hold any dichotimies in the mind at all? It seems to be mental gymnastics, or at least unnecessary. Is there a simpler way?
Some people combine philosophies, such as in existential absurdism. I used to almost consider myself an existential absurdist - "almost," I say, because I don't like to use labels to describe myself. Existential absurdism seems to take the best of all three philosophies and combine them into one. But what does existentialism combined with absurdism look like? Are there any problems with it? Taking what we know about existentialism - that there is an inherent meaning that you can *actually* create, with absurdism that says we don't *actually* create meaning - we just simultaneously accept the aforementioned tensions and rebel against them, and adding to that that existentialism is essentially just a modern incarnation of hope... well, I would say existentialism isn't all hope - there is the societal element which gives it a transmutation aspect. So, I would argue that the combination lends itself to the creation of a process of sorts, in which one acknowledges and gets rid of the bad aspects of themselves while cultivating the good, or, perhaps what is basically a system of virtue ethics.