In fact.
Using a Rubik's cube calculator to find the reduction steps for the Superflip state does not fully prove God's number.
There's a loophole here.
The Superflip state is known as the most chaotic state, but the premise is 'known', which doesn't necessarily mean it's the most chaotic.
Specifically, to prove the God's number of a 3x3 Rubik's cube, there are two methods.
One is to prove that a certain state is the most chaotic.
The other is the enumerative method, which uses the world's most advanced supercomputers to cover all possible states of the 3x3 cube and calculate the minimal steps to restore each.
No one has been able to prove the first method.
Some research teams hope to use the second method, combining group theory with supercomputers, to enumerate and cover all possible states of the cube to forcefully calculate God's number.