When it ends, it ends, and that's it regardless of how many others you created who will now go on to face their own ends. I get that somehow people are able to live in denial of the ultimate extinction of their being, but I never really seemed to be able to get the hang of that. To each their own.
This sounds familiar, perhaps you and I have discussed it before.
My life matters to me as a vehicle for what truly matters: if my descendants are thriving, and my values are upheld, whether I am physically here once I've contributed to it, is completely irrelevant to me.
I will fight to live as long and as well as I can, but only because that increases my opportunity to contribute what I want. Merely "existing" is not my highest value and therefore is not the thing I worry about solely.
It's certainly possible, but I've seen others here express the same sentiment. Another poster once posted a quite insightful comment about Nietzsche that really described a lot of the problems of nihilism that captured the feelings that I've had since realizing the unreality of religion at a young age, so I'm not exactly alone even if I am a bit of an outlier.
It goes back further than that. "To be or not to be" is indeed THE question, or rather THE choice, especially if you have the type of personality that tends to lead to an existential crisis at some point in your life.
In the end, as far as I can tell, there is no obvious "meaning" in life beyond what we decide to attach meaning to. And "to be" is a prerequisite for most objectives we may attach it to.
Having offspring can be seen as an extension to this. It is to decide that "beeing" will go on even after you as an individual dies.
I mean, I'm not trying to be bleak, but do you have any evidence that any of the religions out there can deliver on their promises? Like I'd be somewhat inclined to listen, but extraordinary claims and all that...
I am not the one you're asking but I was born an atheist and discovered religion as an adult, through intellect. Here's my answer from that background.
Ready? The answer is "we don't know." There may be a Gd, there may not be. There may be meaning, there may not be. You can't really know either way.
The answer is that it doesn't matter. The question is what kind of life do you want to live. One that lives as if there's meaning or one that lives as if there isn't? I know my answer. If I get to the end and turns out the meaning was just something I made for myself, and that there's nothing special about my children and my values other than my deep affinity for them... that'd still be a pretty great life.