conix, Since anarchists support authoritarian/autocratic leaders as Trump that faction within Antifa most likely wouldn't be quieter under Biden.
Those in Antifa who see themselves as strictly anti-fascist will simply continue to appear in opposition to your white-supremacy fascists as per normal. The latter could be more active, as they were in Obama's time, which could lead to the anti-fascist people in Antifa being more active too.
It was Plato who said, “He, O men, is the wisest, who like Socrates, knows that his wisdom is in truth worth nothing”