August Landmesser did in no way fight Nazi power. He was a Nazi who refused to split from his Jewish GF, but that is a far cry from actively fighting.
Saying he was anti-Nazi resistance is an insult to all those who lost their lives while or for fighting against the Nazi power.
There was next-to-no meaningful armed resistance against Nazi power in Germany during the war (bar several occasions of power struggle within the Nazi and Wehrmach hierarchy).
Portraying anything like that would not only be fiction, but moreover inconsiderate to the millions of members of resistance movements all around Europe, from France to Belarus.