True for You
Since there are many religions and faiths around the world with contradictory beliefs, but all believing in one or multiple supreme beings, are they all personifications of one ultimate reality?
No. The fact that people believe something doesn't necessarily make it true.
For centuries, western man believed that blood did not circulate, that heavy objects fall faster than light ones and that iron could not float. Many believed the earth was flat. Some still do, such as the members of England's "Flat Earth Society."
Saying that "ultimately, everyone is right" is the logical equivalent of saying that "ultimately, everyone is wrong," because the other religions don't agree that "everyone is right." They all say they're right!
So, for example, by saying "Christians, Moslems, and Buddhists all have a piece of one reality," you are espousing yet another philosophy, one -- like the others -- which everyone else disagrees with! You're adding to the noise of people shouting "We're right!"