Also the whole Astranagant exist in one universe might not necessarily be true. Alpha Gaiden event was considered later a branch that went on it's own (By Sakon) that exist which means Astranagant in that one was used as a black box.
How do we know Divine Wars was not canon and then why would the ovas be canon, or where they not canon either?
Because "canon" is the games. Divine Wars was intentionally not accurately copying the game. Divine Wars, at this point in time, does not reflect the nature of the series, because it does something very different.
Not that I understand how the super advanced Astranagant suddenly becomes a magical focal point which is irrefutably the only Time Diver, when Ingram and Cobray are supposed to be that existence. It just doesn't make sense to me.