Are all religions that involve happiness really the same if taken metaphorically?

I was thinking, look at Christianity or Buddhism. The object is to do something like get into heaven, or reach Nirvana. When looked at metaphorically, aren't they the same thing? Heaven is the place you go when you have been a good person, and realized happiness. Your soul was completely uncorrupt. With Nirvana, you reach that eternal happiness and you separate yourself from material needs. It's the same thing really. that isn't in the name of love (not for creation) is a "sin." It's a material need and you do it to satisfy yourself. If you don't commit any sins, you get to heaven. Same with Nirvana; if a sin in a metaphor for a material need, and you reach that enlightenment that prevents you from sinning, you have reached that eternal happiness. This made me think, heaven isn't a place you go after you die, it's a place you go when you are alive! When you free yourself from the desire to sin, you are eternally happy. 99% of people die in hell. Only the 1% that truly makes that enlightenment make it to heaven before they die. Heaven, Nirvana, and happiness are all the same thing when I talk. Sins are things that keep you from being truly happy. It's all metaphorical, and it's all saying the same thing. What do you guys think?