Life does not have any other meaning other than to survive to the next generation. There is no grand plan, no heaven in the clouds etc.
In the end, it does not matter what you believe, when we die we die. There is no life after death no matter what and how hard you believe.
That's where you're wrong.
There is no proof of a great plan or heaven or whatever yeah.
But there is no proof of the contrary either. And it's not like we understand everything in the universe.
There might be a God. It doesn't mean you have to believe in it of course, but it's still a possibility. No need to abide to a dogma your whole life for a possibility though xD