Welp, Gnosis measure the "gravity" of a being within the Nexus, so one can interprete it that way, but it do not really makes someone more resistent to soul manipulation.
Is like being closer to a higher plane of existence, and at even being in a higher plane of existence when considered divine, the higher the gnosis it have, the more independent from the Nexus it is, so attemps to affect the individual by affecting the Nexus fail. The Nexus is "everything" (how one could notice, few beings already escape their rules) it was and going to be, so reasing the future, or attempting to control their future wouldn't work, they possesses certain influence over the Nexus that allows them to do Reality Warping, as having "higher hierarchy" than others they straight up ignore their immunities (not resistences), etc. But they are just independent, so attacking them with magic, ki and psionics is still factible (unless the being is, let say, invulnerable like Rudra, or omnipresent as Tawil).
As I said, some gnostic advantages aren't general, but "limitations" that few creatures/devices have, such that bell that is unable to affect beings of gnosis 35 or higher, one need to take the general rules. I avoided the nlf o tye disregard of resistences by asign gnosis/natura levels to characters that fight the verse, is not really difficult and it would be unfair otherwise, but someone have to be perceptive about that, I put few examples in the gnosis blog.