#3 Have the match end in a no contest
This is the likeliest option. It, unfortunately, doesn't prevent a singles match, but it can work around some of the limitations inherent in that format.
In Brooklyn, Johnny Gargano and Tommaso Ciampa can get even more out of control with each other than they did in their street fight. The chaos could flare up to such a degree, in fact, that both men could leave Brooklyn on stretchers.
This would prevent a decisive ending and let the story continue to be told toward a proper payoff. It could be the start of Johnny Gargano finding himself again. Such a format would also add something new to the singles match equation that doesn't quite burn fans out as much.
Again, none of these are good options, but that's what's required now. Criticism of WWE's intense house show schedule has been gaining steam in recent times. This is sure to add fuel to that fire. Risking top talent in these meaningless matches weeks before a massive show like this is bound to result in catastrophic scenarios from time to time. Unfortunately, this time, it ruined what should have been the best match of the summer.