Are All Religions the Same? Do They All Lead to God? Does it Matter?

Short answers to the questions in the title:
No
No
Yes

How can all religions lead to God if they all lay out different ways to get to God?

Further, most religions define God/god differently, so how can different gods be the same?

Then there is the issue of exclusivity, which is not unique to Christianity.

Either all religions are incorrect in proposing a way to God, or there is one correct one. If the latter, how can we know for sure?