There’s no denying that the heat death of the universe is a pretty depressing idea.
Somehow preventing our sun to swell into a red giant is also only a short term and meaningless problem in the grand scheme of things. You would have to prevent the heat death of the universe if you want human mankind to exist forever or accept that things will eventually come to an end.
(And in terms of boredom, because I'm guessing that's what you allude to by invoking Q: you can always decide to end your existence after you get bored with eternal life.)
Can you imagine a day in which you feel so fulfilled, so bored, that you say to yourself, "it's enough"; a day in which you wouldn't be interested in what tomorrow will bring? I can't. Hence, by induction, I'd prefer immortality.
I'm probably not going to change your mind, just sharing the elvish perspective.
Firstly, contrary to Benatar, our lives are not "meaningless", even from a cosmic perspective. Our personal problems, concerns, relationships, and feelings are in no way less significant merely in the virtue of the size of the (multi)verse. Your feeling of pain is still pain, whether the universe contains billions of galaxies, or is just 10 light-years across. Same with joy, same with health, everything.
Secondly, our lives are certainly not inconsequential in the grand scheme of things. The whole future of the Sun depends on whether humanity's descendants exist long enough to develop the technology to stop it from going nova and gather its energy. If Earth is indeed the only planet in the observable universe to contain life, then our lives are of tremendous significance. Either we live and hopefully, build grand Kardashev IV-utopia among the stars changing the universe completely, or we go extinct.