Science consists of having a theory and testing the theory empirically. This work focuses on the theoretical model, and references numerous studies supporting their position.
therefore without any real evidence consciousness is just an illusion and we as people don’t really exist, just sort of… believing we do because of brain juices
That’s not what it says at all. What it’s actually saying is that what we perceive as consciousness is a byproduct of the subconscious and the likely evolutionary value of this construct is to facilitate social transfer of experience. It’s an argument against mind-body dualism which is itself a deeply unscientific concept.
Furthermore, the whole idea of a soul is laughably unscientific since it posits that there’s this magical entity that’s not an emergent property of the physical reality.