4. Do the Borg have any weaknesses?
Were you to encounter the Borg, unpredictability would be your friend; the Borg would be susceptible to any tactical strategy they haven’t previously seen.
Starfleet has designed weapons specifically to battle the Borg. The Defiant, for example, was one such starship; its phaser cannons rotated their frequencies so that the Borg could not adapt. But brute strength is not a long-term solution against such vast numbers.
The Borg’s confidence is their undoing. One of the Borg’s quirks is that they do not attack unless they see their targets as imminent threats. Borgs will often board ships or beam down to planets just to survey and scan the technology and biology; they will not appear aggressively hostile at first. And during this small window of opportunity, Starfleet crew members have boarded Borg cubes and walked around unencumbered. This is an excellent opportunity to gain tactical advantage before the fighting inevitably starts.
The Borg are particularly susceptible to tech-based attacks.The most successful ones have come from scenarios where Starfleet captured a drone, established a neural link with it, and compromised the Borg’s defense systems.
There have also been scenarios, suggested or acted upon, where Starfleet used drones or assimilated humans to upload viruses and malignant programs to the collective. These instances have only been possible, however, through a combination of specific circumstance and dumb luck, and they would be nearly impossible to replicate.