science has probably proven there is no god / afterlife
Well, for one, you "probably proven" doesn't make a whole lot of sense unless maybe you've got a paper waiting on peer review confirmation. In any case, it is exceedingly difficult to definitely prove something isn't for cases like this. Does every bit of evidence point to 'no'? Yes. However, it's still technically not proven to be false/absent.
Anyway, that's not the actual important part here. One human lifetime is generally a long time. There are lots of meaningful interactions that a person can have in that time. I would argue that, since it's not an eternity, the pressure is on to do something better with your life. That doesn't require gods or afterlives. Volunteer, meet up about hobbies, find a social group, etc.
we inherently know this and want there to be something after death, because it feels right, or more meaningful
I disagree. For one, if you get do-overs on life or an eternity to do whatever, isn't it inherently LESS meaningful since there are no stakes? Secondarily, I personally don't like the idea of trying to exist for an eternity; that sounds like it always ends in boring monotony... at least so much as something 'endless' 'ends' anyway (English be silly).