You don't even need to get to the point where your consciousness is inhabiting other people to get into this. Today's you is different from yesterday's you and tomorrow's you - you all have different experiences and memories. The you of this moment only exists in this moment and is already gone.
I am definitely not as well read as I like here but I do think about this subject a lot and in particular I've been chewing on Time.
Lately I was thinking, why don't I feel more anger right now at past me or future me? Like you say, those could be seen as different people than me.
Past me made present me fat. Future me implicitly prevents me from enjoying this cake by pressuring me to do things that won't result with him also being fat.
When I start work in the morning, I've been assigned a task according to the goals of past me. Why should I care what that guy wanted? I want to play Elden Ring. Ah but there's future me again, mad that he can't play Elden Ring because he had to rush to finish work I was supposed to do. Well fuck that guy, I might die of an aneurysm before his time, then none of us get to play videogames!
But I don't really feel mad at past or future me because I recognize them as me and our goals are mostly consistently aligned. I'm thinking that my identity and Mind is very deeply rooted in the Time dimension, though not clear on all the implications there. I do at least feel that memory is a critical part of Mind. The continuation of my memory timeline seems most likely to be what Me is.
This only says that consciousness is ever-mutating. Most would agree on that. But most would disagree on the death question: afterlife, another life, or annihilation.
