If I snapped my fingers and suddenly I became immortal. Okay, cool, I'm having this experience now chatting in this forum. Now, let's pretend that some catastrophic fate, end, or "change" to the universe doesn't occur and I'm not completely obliterated by processes outside of my control, or changed into some form of matter, energy, or whatnot that is completely unhuman or unlike what I am now. Let's say some time passes from this moment and I am precisely 18,562,335,335,472,920,608,480,024,252,466 years in the future from now. So much time inconceivable has passed, that I probably wouldn't be able to remember or recall this moment if I wanted to. This moment is meaningful now, if only in the sense that I am taking part in some kind of connection to others. I am expressing my thoughts, thinking through my thoughts, possibly even working on self growth and betterment just by my engagement here.
But...reality isn't so kind to guarantee any kind of "linear progression" or definite better future or state of being for me because of whatever decisions I do or don't make in whatever present moment. Any positive change can be unexpectedly undone. So if infinite existence was suddenly a thing, any present moment is still inevitably doomed to insignificance just by the magnitudes of time passing, eventually.
But that would be okay with me. Because right now, I'm not 18,562,335,335,472,920,608,480,024,252,466 years in the future from now. I'm here right now, that's what matters. And in an instant the present has already passed and a new instance is the present, and that is what matters. Holding onto the moments that have significance for as long as it remains relevant, and letting go of those moments that no longer occupy identity forming significance, that's the human experience and predicament we are in.
To be paralyzed by pointlessness or throw both middle fingers up to pointlessness, that's for each person to figure out what to do about.