The AI empires have crumbled at this point.
The dead space that I owned in the west is gone, and the Tempest is knocking on the door of actually important systems. So far my bastions have held them off with relative ease. The territories I conquered in the east are also getting tempested, but thankfully they seem to leave the planets I'm eating alone.
Might have to frigate cloak cheese this one. The alternative is crusading through half the galaxy, taking an L-gate, and fighting them properly from there.