It is I'm just basing that off IF they they retconned her powers slightly. The Legion should've guess that off rip but hasn't said a word about the Phantom zone.
They’d be trying to find a way into the Phantom Zone to see if they’re there instead of automatically assuming that they’re dead. In actuality, they’d be after the same Phantom Projector that Lor Zod is after on New Genesis. It’s why I assume that she doesn’t have those powers in this iteration or at least they don’t know that.
Another thing I noticed is that the Legion mentioned being camouflaged hiding in the present since earlier in the season, but we had the after credit scene episodes ago that showed otherwise like that wouldn’t screw up the timeline.