If the universe started from a single point, how can there be no center?

But there is: https://www.google.com/maps/@35.0840874,-106.6221466,3a,75y,...

Consider the surface of a sphere. The sphere has a center, but it's not on the surface, so in a sense the surface has no center.

If you find that unsatisfying, you could posit that the universe does have a center, just not as a location in space that anyone could visit even in theory.

It didn't start from a single point - or at least - regardless of where you are, the the universe appears to be expanding outward from your location.