I think it's important to think about marriage separately from raising children. You can do the activities separately or together.

For me, my spouse is someone I can implicitly rely on and vice versa. We are a team working towards our shared purposes, but we are still individuals. We each have skills that make the others life easier. It's a lot easier to get a ride from a spouse than from a friend, and a spouse will be more available to help tend to sickness and injury. That sounds emotionless, but of course emotions and emotional support are important too.

For me, having a spouse where we have compatible ideas on children, money, climate, travel, and most things is like an easy button for life. Research and problem solving is easier with two people. Decision making can be harder though.

If you marry someone who doesn't have compatible ideas, there's going to be a lot more conflict and a lot more deep compromise, and that may not be as appealing. And, of course, people change, and exiting a long term commited relationship comes with trauma, so there's risk. Maybe none of this feels appealing to you, and that's fine. There's some social and legal pressure to marry for lots of reasons, but we live in a world full of social and legal pressures, and you should reject those pressures if they don't feel right to you.

Raising children is a whole other thing. I don't think people should be pressured into it, and it's best to be on the same page as a potential spouse before considering marriage, otherwise one spouse is likely to have to make a big compromise and that's not great. Personally, I find raising children to benefit from a team approach, but it's not required and a marriage is just one way to form a child raising team.

It sound you are looking for datapoint to easier accept your lack of meaning in life. You can also do the opposite and look at the happy partners & families to prove yourself wrong.

But I understand, however I hope you find it, in which way works for you, it does make life much richer.

For me family is one of them & buddhism another one.

If I can give advice, the easiest way to experience meaning is to serve & help others. Easiest is to do voluntary work in obvious helpful things like food serving etc. Something where you just enjoy & give and not think deeper about what the point of it all is.

I think there is quite a bit of nihilism in Western evolutionary materialism (all our feelings are just side effect of evolution). But that's a very limited view on reality. Not sure if that's also part of your experience, but I do see this cause similar feelings to smart & technical people around.

Lol, I was raised Catholic; the serve others thing is quite a big part of the dogma, and I don't disagree with that necessarily (unlike quite a bit of the rest of that religion), but that doesn't mean that it works for everyone. Some people are just wired differently; the meaninglessness creeps in no matter the volunteer organization; the therapy, the drugs (licit or otherwise). It's an experience since young childhood and seems unlikely to change markedly. I'm actually quite happy that it's not something I'll ever have to subject a child to (and the probable hellscape that we're leaving them; glad I'll never have to have that conversation either). It certainly could be a post-facto rationalization on my part, but perhaps it's just the way I am and ever was. Honestly, accepting that has brought me peace as much as anything.

All the best.