Yup, I think that's what we will see in 'Picard'. To make matters worse, the Romulans then captured many of these individualized drones and used many of them for their sick secret weapon experimentation. That's why they built this prison camp where they held the freed drones (including Dahj) as captives.
That's why Picard recruits Seven and Hugh into his 'A-Team', not only to help him to find Dahj, but also to find other individualized drones held captive and liberate them. They were too late to save some of them
but in the end managed to save quite a few. including Dahj. Picard and his 'A-team' are then hunted down by the Federation, since elements within Feds (most likely Section 31) are in cahoots with the Romulans and are behind the making of this secret weapon.
That is similar to the theory I am still going by, but without Section 31, Janeway destroyed the Borg Collective in the Voyager finale, that is done, they are gone. But Romulan extremists, who want to rebuild their empire, find an abandoned Borg cube and are trying to weaponize Borg tech.
Really the Borg are a one-trick pony, they very powerful, but have very little use for schemes and subterfuge relying almost exclusively on brute force, while the Romulans were good at scheming, but often came off as a paper tiger in the TNG, they do something sneaky, get foiled, slink away and return in a couple of weeks to do the same thing.
Both the Borg and Romulans seemed like played out villains who the writers ran out of ideas for (though with the Romulans it never seemed like the TNG era writers had a solid plan for them). So giving the Borg's toys to the Romulans gives both of them some new blood. A ruthless Romulan admiral who fancies himself the new Praetor could create all sorts of horrific weapons with Borg tech, turning his troops into attack drones armed with disruptors and able to assimilate anyone they meet, instantly enslaving them and adding to the attack drone force. Or take Borg nanoprobes and reprogram them to be lethal, let them loose on a planet and have them devour all the life on the planet or secret implant nanoprobes into a victim so that person can be an agent without them even knowing it.
Take the Borg's tech, weaponize it and give it some militaristic psychopath who will do anything to return to the ''glorious past'' and you have a supremely scary villain. There was a short story in the Star Trek: 7 Deadly Sins anthology, where a human mercenary was hired to steal Borg tech and intentionally infected the crew of an illegal salvage ship, turning them into Borg drones, just she could sell them to her employer, that is a good horror story and someone who uses Borg tech for their own petty purposes is pretty scary.
I also think Picard, 7 of 9 and Hugh would find someone who is willing to weaponize Borg tech for their own purposes as a particularly morally repulsive individual. This also fits with the trailers, where we see a Borg Cube with blue force fields, Romulan ships, run like a prison camp, with Romulan guards and Romulan writing inside. The Tal Shiar or other Romulan Extremists likely have no problem experimenting on people in order to make better attack drones and not care if people die during these experiments.
