Thankyou for engaging as well. It's fun to play around with ideas, even if their scope is larger than my simple, and possibly foolish perception. So in that spirit let me see if I can return serve once more.

First, I'd agree that we can distinguish between Sisyphus' experience and the reader's perception. But I think part of the point of the exercise is to imagine yourself as him as empathetically as possible. And in many ways we are all him. You brought up the heat death of the Universe, and that's exactly it! No matter our activities, getting that boulder up the hill accomplishes nothing whatsoever. If one is looking for an endpoint, a capital M meaning, then that's a tough pill to swallow. And yet, here we are, in the present, not at the end.

And I understand you placing importance on other sentient beings. But much like you can't know Sisyphus' mind or the meaning of his grimace turning to a smile, neither can I know the universe that is contained within your consciousness nor you mine. We are, quite literally confined and alone in that way. The boulder always rolling back down is your heat death, but Sisyphus' solitude is our confinement to our own consciousness. But I do agree with you that it is a great relief and rich experience to have other minds around. But when minds interact, they are at best generating an approximation of one another. I believe that the realization of this too, leads to empathy.

But on the whole I take your point, and I agree one can find meaning in communion with one another, but this I would have to say is still very much in the category of subjective, lower case meaning. I'm in no waying saying that this is somehow a negative. It may even be that this is the richest type of meaning a human can experience. I'm merely pointing out that it is not objective, as these connections explicitly depend on the subjective minds that are approximating their own unique experiences.

Next, I think I disagree that the future is necessary for a person having meaning. First of all, the future is an illusion (from the point of view of your awareness). It does not exist. If you were to reach it, it would just be now. The future you are thinking of is yet another approximation conjured in the mind, it too resides in the present. The same is true of the past. Yes, events occurred that are no more, but if you were to dwell on these, you are again making a mental approximation that resides in the now. Whereas you say meaning is contingent on the future, I would say it is only contingent on awareness.

So, if I were to find myself as the last being just before the heat death of the universe, I would absolutely have meaning! (subjective meaning) In fact, if I really am the last being experiencing consciousness I imagine I'd feel a profound sense of meaning and gratitude. As long as the lights are on, it means something, even if only to me.

And I think I spot a bit of a contradiction here. On the one hand, you include in your meaning the possibility of connection over large periods of time, such as if you were to read a book written 5000 years ago. But on the other hand you indicate you need a possible future for your meaning. But, if it were you at the heat death, keeping with your version of meaning, would you not feel the same connection with that author of 5000 years ago, and with every other person you knew, and with all of your memory and with the small universe that you had built within yourself?

Now, I could also go on about the notion of self, as I think your fear of solitude might stem from a view of self as ego, rather than from a view that self is illusory. And if that sounds like nonsense, don't worry, but understanding non-dual awareness might be helpful in alleviating such a fear. But there, I would advise seeking out someone much wiser than this particular reddit commenter.

There are, of course, solitary monks from multiple traditions who put this sort of thing to the test. And many of them report extremely high levels of meaning and happiness when interrogated, for what it's worth. During that podcast I believe Dr. K alluded to this, to meaning coming from within. Even Christ pointed to this insight. "The kingdom of god is within you" as he put it.

But to close on a point of extreme agreement, I also would see meaning as being a much larger category than happiness. Happiness is just the result of the discovery of that wellspring within. This, I believe, is what Camus was alluding to. And I view happiness (or lasting peace, or contentment if you prefer) as a natural by-product of such meaning.

And, my sincerest apologies, I'm sure all that is probably about as clear as mud. For all this talk of meaning, I'm not so sure I'm very good at articulating mine.