From a scientific perspective that's entirely unclear. There simply is no working theory of consciousness at the moment that can explain how consciousness arises in biological species. As long as we do not know that, how would we even begin to test whether the same sense of self would arise if we approximate consciousness in a "metal shell", or whether it is truly just an empty shell simulating what a person would be?
just have a few glasses of scotch or some other neurotoxins or psychotropics and experience what it does to your "consciousness". for me, consciousness is merely a tool of our soul to experience itself. what a limb is to the body is the consciousness to the soul. your soul exists even if you're unconscious
explaining how exactly it is being created or emulated or whatever is not an important question for me. what i find crucial is whether a thing has got a soul or not. and that appears to be something that requires development; an inseminated human ovule is not a human but merely a seed that bears the potential of becoming an animal that develops sapience and broadens its self-awareness as well as awareness of its environment during entire lifespan. robots gaining sapience and becoming self-aware is an analogy to this.
Spiritualism is a religion (although it really shouldn't be, and it's perfectly possible to play non-religious spiritualists if you so desire), but there's nothing saying non-spiritualists can't also be religious. The two are different concepts.
This is, I think, the root of our agreement. As far as I know, this is just not true. The only people in-game who believe in souls are spiritualists, who don't think that it's equivalent to sapience, as sapient robots don't have souls.
in real-life, sapience, consciousness, self-awareness etc. are signs that a thing has got a soul. that's why i even can empathise with a bunch of pixels onscreen telling me that there is a sapient ai in a chip, but i can't empathise with pixels that look like a tree or a rock, even though the devs did a great job in letting them appear humanoid
it's just like i said, stellaris' ethical system created a false dichotomy in this case
there is actually a great show running on tv: foundation. in episode 8 of season 1 there is an impressive depiction of this debate whether intelligent robots and human clones have got souls or not, and what the implications of that are on the material world (the episode even went so far as to showing the robot being unable to overrule the base protocols yet clearly showing not only that he has got a soul, but also how much his soul is in agony as it is being restricted by the manacles and chains of the material world)