1 .Recasting the actor would cost way more than that if they replace Ezra from the whole movie, it would double their budget.
2. HBO Max would involve buying some actors out of their contracts which Erza being one of those, I really doubt WB would want the press of giving him more money right now
3. No other company is going to buy the movie for the same reason WB is having issues with it
4. They could in fact lose more money when it comes to costs like marketing and distribution
Here is what they can do
1. Cancel the movie reuse what footage they can in the Batgirl movie and planned Supergirl movie, so it's not a total waste. Right now think is this most likely one. because it's the cheapest one to do and avoids least amount of losses and bad press.
2, Wait to see if he killed him self, least then they don't have to worry about giving him more money and could play the mental health card that is harder when still alive, if that happens a cinema release makes sense if they especially donate a % to a mental health charity. ,however if he kills anyone else it's game over.
3, He hasn't been jailed for anything yet but clear this won't blow over any time soon, could wait to see if he gets sectioned then dump it on HBO Max but if he is charged with anything involving kids it's game over.
4, Reshoot every bit he is in, this would be like reshooting most of the movie, would put the budget up to amounts where it could never be profitable however it won't derail their business plan when it comes to DC going forward and it will be good press right now for WB. But Warner Discovery is currently trying to cut $3 billion in spending from the company so spending an extra $150 million on a movie where most of the cast would be needed to paid again and they may not be able to get all the cast back is a bad pill to swallow.
I used to think they would just reshoot the ending with a new actor taking over the role, but with more and more stuff coming out, I really doubt that can do that any more. But hey WB only have them selves to blame
This happened before the Flash movie started filming, they had their chance to recast.