50% of myself would say yes, maybe Gridman split himself into those components so that he won't lose part of his memory (eg. The NGJHS were Gridman's almost accurate interpretation of God Zenon) while the other half just that SSSS.GRIDMAN is actually a series that pays tribute to 90's mecha anime and Ultraman as a whole. If you watch the VERY first Brave series, Brave Exkiser, its about a cop from outer space whose true form is an energy life form that assimilated with someone's police car. Sounds familiar?
Technically speaking, its just unhabitable and/or reduced to wasteland. Getting shrunken isn't mentioned however, since being on Earth means that any celestial bodies from faraway looks smaller, just like the moon. Or, its just a sci-fi nonsense since the crews can't really picture Sturm properly.