I think innovate is being used narrowly, to suggest the Borg are not creative. They can adapt to many things they encounter quite rapidly and at least potentially novely (though in practice they usually just, like, modulate their shields and shit), but they aren't capable of creative thought for the most part, which would be a big part of why they do what they do—growth for them can only come from expanding the database of experience each individual brings.

Which, your original point would presumably still stand because it would suggest that the Borg simply being aware the Q exist isn't enough for them to conceive of how to take action against them, should they want to. They'd require direct interaction with the Q to understand and begin adapting to the threat they pose. Assimilation of El-Aurians also tends to explain the Borg resistance to time/reality shenanigans; they get that directly from them (and/or other similar species) and the Queen may or may not hold that particular ability individually (I'd expect every drone possessing it would probably risk Collective stability issues, as experience of the changes and variation would bring experience of individuality pretty much inherently).

The Borg are super interesting, and I'll be kind of perpetually bummed the Jurati Borg are likely to be ignored, especially by main canon works, because they're full of contradictions and it's generally not explored much in depth. The Queen pretty clearly feels the need for discrete companionship (Picard/Locutus, Data, the Queen's extended courtship of Jurati), hinting that the Collective is on some level inherently unstable as constituted. But they're fucking prized as an antagonist because they're faceless and usually unstoppable so violence against them is much more free than against any other species in the show, so we never much unpack that. Even their apparent extinction almost certainly doesn't stick because eventually someone's gonna want to be, basically, lazy and have an easy monolithic threat to use and the Borg will stay irresistible for the purpose.