I am going through a divorce with a physically, verbally, emotionally, mentally and financially abusive soon to be ex. She signed my name to a check from our checking account that was made out to both of us and deposited into her individual checking account. The check was returned "altered/ficticious" and the she did not receive the funds. If I do not file a police report but wait until our trial and tell the judge to discredit her, could the judge give me everything and her nothing? We have one minor child together who does not want to see me or talk to me now.

Default divorce, the judge bangs the gavel and it's over? You get everything and she gets nothing, based on an alleged forged check?
Divorce court isn't small claims.
You should report the forgery now.
Don't be surprised if the court isn't shocked and amazed, since spouses do this a lot.

... If I do not file a police report but wait until our trial and tell the judge to discredit her, could the judge give me everything and her nothing? ...

Can a snowball retain it's solid state in the infernal regions?

Not likely.

Default is not the outcome where both sides show up and defend their respective sides. It's for when one party fails to defend at all.