God did not create all those unique religions and philosophical outlooks. That’s the problem. God only created one religion; man created all the rest.
I would not put it so bluntly.
Most world religions are natural religions. This does not automatically mean they are false or that God has nothing to do with their genesis. God gave us all an intellect capable of coming to know of His existence without supernatural help and a will that is naturally ordered to religious piety.
In a state of nature man observes the created world and comes to realize that it all must come from a sacred Creator. He then experiences an almost instinctive desire to serve and sacrifice to this Creator. Hopefully he does so, empowered and guided by divine grace.
Unfortunately man is also a fallen creature, and there are other spiritual forces at work other than grace. Thus natural religions quickly become unnatural. Superstitions creep in. False gods are imagined. Mythology is tainted with sex and sin. In many cases the idea of God Himself is tainted, sometimes to the point that he could no longer be called God.
But there is also such a thing as revealed religion. Judaism is the only pre-Christian one we know about. Here God actually revealed truths about Himself, provided a national religious law, set up a system of sacrifices and festivals similar to those of natural religions but ordered towards something higher.
Then came Jesus Christ. This is the key to the OP’s question. God Himself became man and chose to be the great sacrifice, the bridge between the humanity and divinity that natural religions had tried in vain to build and that Judaism had only anticipated.
Looking at Christianity as simply a world religion, it’s easy to see its claims to universality as provincial ignorance or, worse, presumptuous cultural imperialism. But if you look at what Christians actually believe about Jesus Christ, it becomes clear that either our faith must be tragically mistaken, or else that the Messiah we put our trust in is indeed the only possible path to eternal salvation.