Yeah, I just wonder if it is entirely impossible, or there MAY be a way, even if theoretically (so far). Or is it like "it certainly can never happen"?

You imply microorganisms capable of digesting glass, stone, and sand, via a hydrofluoric-acid-concentrating biochemistry that I suspect is not even remotely possible in Earth's atmosphere, which is something of a relief because if it did happen, it would almost certainly end all other life on Earth within a span of years to decades.

I do not imply their existence. My question is, can they exist or is it completely impossible, even theoretically?

Nothing is impossible in theory.

OK, well, is it completely impossible in practice? I just want to get educated! Gosh.