People believe in those things because they need to but there is not a single piece of evidence supporting heaven/god. ''On the contrary many people know there is a higher meaning and purpose'' They think they know but it doesn't mean they do. They think the purpose is to go to heaven but they never think what is the purpose once you are in heaven or what is the purpose once you are reincarnated. It doesn't seem to me that there could ever be a good purpose because what happens once you reach it? Perhaps we can't understand it now because our brain is not capable of understanding but imagining gods is not going to do anyone any good.
We are here and thinking. We inhabit a universe that appears to operate by cause an effect but contains a complexity and scale that is so overwhelming that out understanding of its workings remains infantile. This is certainly evidence that cries out for explanation.
The leading scientific dogma of today is no more rational then the religious explanation probably less so. My son came home from school the other day explaining how the universe started. Curious as to what they are teaching in his school I prodded him for more information.
"How did the universe start?" I asked
"There was a big bang and all the matter in the universe appeared." My son replied
"Where did the big bang come from" I queried
"It started as a big quantum fluctuation that made all the matter appear" He responded
"Has anyone ever seen a quantum fluctuation actually create matter even something as small as a single electron or proton?" I queried
"Ummm" he replied
"Do we have any evidence that a quantum fluctuation caused a big bang?"(Thoughtful Silence)
The answer of course is that believing the universe started as a random quantum fluctuation is entirely one of faith and assumption. It is nothing more then the application of a nihilist worldview a theology if you will to creation.
I choose to embrace a different faith and take the position that creation logically implies a creator. We live in a universe that demonstrates cause and effect and this alone strongly supports belief in God over a creation of random happenstance.
Ultimately God is a matter of faith but then so is a belief in nihilistic randomness. Refusing to take a position or waffling and claiming the evidence is not clear is not a valid choice as we must all engage with the business of living and that business requires us to reference our core values on a frequent basis. Refusing to choose leads ultimately to incoherence or subconsciously living by assumptions without thinking about them.
As to what our purpose may be in heaven I would agree with you that this is something that is probably beyond human understanding. I am someone that tends to focus more on the here and now so I have not personally given it a tremendous amount of consideration but others have.
Here is a link to Bruce Charlton's musings on what that purpose may be. It struck me as a reasonable answer although I am sure there are many differing opinions on this topic.
What is the purpose of Primary Thinking - for us, and for God?
http://charltonteaching.blogspot.com/2017/10/what-is-purpose-of-primary-thinking-for.html