Too many factors to really consider at this time. Wisconsin's self-defense law has already been eroded in court, where "too extreme of self-defense" invalidates it. They could argue that an AR is too extreme, or that shooting at multiple people is grounds to invalidate self-defense. The jury could be tainted/poorly picked, or a bad defense lawyer may convince him to just plead guilty to "lesser" charges or provide no defense. A lazy/bad judge may allow for tampering or political leakage in his courtroom. Furthermore, a Biden victory may create pressure to obey the mob/left for court cases that ended up on the wrong side of the riots protests.

For example, the prosecutor would only need to argue that an automatic rifle is not a measured response to having a bottle thrown at him and someone getting in his face. This tainted version of the narrative (ignores that it was a molotov that was thrown at him, ignores that the initial protester assaulted the teen) could then be used to invalidate his self-defense.

Ideally, you are correct.