I mean, the only thing you can do VS a mass DMCA is to be super anal about the laws, stuff like requiring legit digital signatures, and using the full amount of business days per takedown to process them ,and overall be as much of an asshole as possible in extend of the law when receiving a takedown request, you really can demand a lot of stuff to "make sure" the dmca request is legit. But it's a balancing act for no much gain other than ruining some lawyers day.
Overall, it seems it's over, time to pick up the pieces and grow another head of the hydra.
Overall, it seems it's over, time to pick up the pieces and grow another head of the hydra.