I dislike using BFR, but if BFR is implicitly allowed Batman can use it to win the battle.
Or with 2 hours prep he could destroy Apocalypse using some satellite laser like he probably have in Justice League headquarters.... But this is not logical because Batman doesn't know the durability of Apocalypse for him to resort to such a drastically dangerous weaponry.
But yes, I agree that the OP is too optimistic about Batman's abilities. Batman with 6 months of prep would definitely find a way against Apocalypse.