Every movie with light speed travel gets the dilation of time wrong. And there is no way to go 'back' in time.
But a big problem is that the wormhole that allowed the current Humans to 'get out' was built by Humans who got out.
Oh I know. If I gave the impression they go back in time, I’m sorry. They didn’t and didn’t even attempt it.
It’s just a cartoon, after all. :-)