The calculation uses m_p , which is independent of G. Deriving G to 8 ppm from m_p is not necessarily "meaningless", or at least it's statistically non-trivial. It is not just "G = G".
You mention the "uncharged case", but ordinary matter is not mathematically neutral. By focusing on the uncharged case only, you ignore that this is an attempt at unification. The model proposes that geometry explains both interactions. You cannot remove one of them, because in nature they happen at once.
The rest of your remarks don't seem "uncharged" at all, but the opposite.
You mention the "uncharged case", but ordinary matter is not mathematically neutral. By focusing on the uncharged case only, you ignore that this is an attempt at unification. The model proposes that geometry explains both interactions. You cannot remove one of them, because in nature they happen at once.
The rest of your remarks don't seem "uncharged" at all, but the opposite.