You want a Country of Toronto then; segregating the GTA out of Ontario won't change the fiscal situation very much. We could increase taxes but we could do that now too. You don't need to look further than Toronto Property tax rates over the last decade to see how that argument would be resolved.^ I disagree.
We will not have a Province of Toronto until the taxes reaped from Torontonians are returned as investments in Toronto.
GTA would be massively in the "have", more so than Alberta, and much of the rest of Ontario strongly in the "have not" category; substantial equalization transfers would apply.
Absolutely no other province would vote for a Province of Toronto without ensuring equalization is maintained and Toronto doesn't even have any natural resource revenue it can pull out of the equation (most provinces have at least one industry that is treated as an exception).