Did Enki anticipate this and tweak us genetically to activate at this time, and wake up, a kind of poison pill designed to stymie his brother’s intentions?

This was not done by Enki but was done divinely, and it was done with a parallel desire by the Enki ruler to see that the inheritor of the next segment for his brother would be an even greater challenge, and this is the kind of game they have played among themselves in prior exchanges. This was used as an opportunity for the divine realm to help humanity and also not incur a backlash from the Anunnaki.