I studied art up to the first year of university, until discovering that academically, it wasn't for me. Family friends were also working artists (and one cartoonist!), so I'm not unfamiliar with the world.
There's plenty of art criticism and analysis that I can get on board with. But the "liminal" craze seems like just that to me: a fad that appeals to some people because of its mysteriousness, and so on. It has no real broader significance. Just because someone identified an aesthetic with a term doesn't turn it into something more significant.
It's as if someone identified the "spooky" aesthetic and started talking about the X-Files and Blair Witch (dating myself) as examples of high spooky art. I suppose one can make a case for it, but so what? It's just... pointless.