bearing in mind that I got my degree from a cracker jack box I’ll say that my contact with “ontology” is out of lit/critical theory. A basic concept being the literary work as closed ontology or entity in which internal processes operate, and then a question from there is to who/what does this ontology permit entry or communicate with.
Been a long time since I read any of this stuff seriously, but recall for example Gertrude Stein writing about her assertion that literary “masterpieces” (in her terms) exist as ends in of themselves, and their communication/legibility is a paradoxical hindrence: her example was that oration and letter-writing are rarely “masterpieces” of literature.
She also discussed literary works and narratives, as discrete “blocks of space-time”, in the way that the dimensions and I suppose chronological and physical rules of these “ontologies” vary
This is the miniature concept, the larger one being theories like Marxism, like those on modernity/postmodernity from Frederic Jameson, Postcolonial theory, Deleuze, etc - all brushing up against the apparent fact that our present version of “modernity” or in other words our ontology/existence, is shaped by and limited by globalized capitalism (base <-> superstructure), but that other possibilities have and can (hopefully) exist.
But this is of course all art/social theory - are physicists really as reality-skeptic as social science critical theorists can be? Is quantum mechanics that disconcerting? And dumb but sincere question: would it help if you had a huge microscope or something?