We say "change your mind" and not "change your brain" for a good reason. To change your brain is a physical act to change your mind isnt. We perform this non-physical act hundred or thousand times per day yet you think you need for the sake of clarity to not to get stuck in hypotheticals?Sure, it's possible, but there is 0 reason or evidence for us to think that this is true. To clarify I am sticking to the facts here and trying to not get wrapped up in hypotheticals. All signs point to the mind originating in the brain, so it's sensible to assume that this is the case, unless evidence is unearthed that suggests otherwise, at which point in time it would be wise to revisit that assumption.
I would say that what makes you more truely human isnt your physical body which is largely still an animal but exactly this non-physical "actor" your mind with all its various capacities for analysis, deduction, abstraction, imagination etc. And although I dont think you are your mind its probably more correct then to say you are your body.