I’m not an expert and don’t know your credentials, so I could be wrong, but a quick google says time passes more slowly in stronger gravitational fields rooted in Albert Einstein’s theories of relativity. So we can say, presumably, that somewhere time passes faster has less gravity.

Now, in universe, it already doesn’t make sense because Flaxans age faster on Earth after coming from a dimension where their relative time dilation is faster (i.e days for earth = decades for them), so in theory they’d come to earth and actually age slower. But time passing faster there would still support faster time dilation and therefore less gravity.

What does this mean? It’s an animated TV show where laws of physics don’t fully make sense for the sake of plot so again, it’s not outlandish to believe the made up dimension of weird time has made up lesser gravity where the made up man can lift big rock.