What Were the Klingons and Romulans Up to When Earth Was Attacked?

Starfleet’s assimilation happens quick enough that it’s probably no surprise that neither the Klingon Empire nor what is left of the Romulan Star Empire—after all, it’s still in a rough state after the events of season one of Picard and the destruction of Romulus in the 2009 Star Trek movie—have time to show up to help.
But at the same time, were there no changelings trying to infiltrate them? Yes, it was Starfleet intelligence and Section 31 who experimented on Vadic and her allies specifically, but the Klingons and eventually the Romulans were enemies of the Dominion too.