I don't agree with that. I don't see what's impossible about understanding consciousness as an emergent property of matter in the same way that many individual ants collectively bring feats that you can't explain looking at a single ant.

the problem is that every ant in the ant colony is ostensibly a purely physical phenomena (at least, we usually do not concern ourselves with the ant's subjective experience as much as their information processing capabilities - we watch their movement, monitor pheromones and chemical signals, note the structure and changes to their nest, etc., all very physical and mutually compatible ideas), whereas something like the concept of subjectivity is entirely incompatible with our ideas about physics. you can do 'information processing' without subjectivity very efficiently, as with any calculator or computer, so subjectivity seems entirely superfluous in the sense of a purely physical explanation.

The fact that we haven't gotten there just yet doesn't mean it can't be done, or that biology is completely independent from physics and/or psychology completely independent from biology.

you have to prove something is true before you believe it, assuming 'we will figure it out later with no significant modifications to our theory' is intellectual laziness/unsound epistemology. no one is saying that biology is completely independent from physics or that psychology is completely independent from biology, i am only saying that our understanding of such topics are far from a unified 'theory of everything' and are therefore incomplete in a non-trivial way at best, and fundamentally flawed or incorrect at worst. obviously the subjective component of human consciousness is somehow related to brain function, we can prove and accept this empirically without any kind of metaphysical claims or assumptions tacked on. obviously physics isn't completely BS, it helps us solve a lot of problems. but at the same time, we cannot fully explain (i.e. reduce, hence why i am arguing against 'reductivist physicalist realism' and not non-reductivist versions of physicalist realism such as the one you seem to espouse) psychology in terms of atoms and their locations and velocities and mass without losing information. the fact that you believe in 'emergent processes' itself means you are likely not a 'reductivist' physicalist realist like i am arguing against.

I just don't see how from "we don't understand consciousness" it follows "therefore it can't possibly be explained with physics in the way we understand physics".

usually when a theory fails to account for a phenomena, it is assumed to be flawed or incomplete somehow, and the significant explanatory gap for subjectivity in physics and information processing (what information processing algorithm produces a first-person experience? is there a fundamental particle or wave of subjectivity, a 'subjectron'?) would seem to imply a non-trivial incompleteness or flaw.