Depends how you fight. Some union busting tactics are illegal, others legal and a few skirt the borders of illegality.

Even if they do do it illegally, the justice department has to be motivated to go after them. Which, with a Biden administration that is close to Bezos is unlikely:

https://www.reuters.com/article/us-usa-election-tech/amazon-...

These workers can't really rely on the justice Department.