For one, the Cybermen don't rank as a higher threat in my eyes as the Borg. Indeed, they lose the Cyber-Wars against humanity in the Doctor Who continuity.
And yet we know from Nightmare in Silver
that the Cybermen grew to be a significant enough threat that an entire galaxy had to be destroyed to stop them.
As for the Borg Queen not existing in this time period, I'm sure she implies in First Contact
that she knew Picard when he was Locutus.