A nation state is an artificial construct defined by artificial borders. Nation state sovereignty most definitely invokes those borders.
But humans are natural not artificial. While I argue that SSI currently relates to legal or more generally noun-like identity — rather than the verb-like, more natural conceptualizations of identity — it is being designed to bleed into every micro-interaction in our quotidian lived experiences. And this is deeply worrying.
There are absolutely no hard borders in natural living systems. Perceptions to the contrary may be expected but remain entirely subjective, and I address this very point at greater length in the original post in this thread (heading: An ecology).
Drawing hard borders is your personal choice driven by one's own goals, context, values, and cultural lens. Drawing them makes no difference in the ecology of the whole ... as Gregory Bateson noted, they just form part of the very ecology they were supposed to delimit.
But drawing hard borders does make a difference when concreted in technical code from which Alice has no escape. Alice's context, values, and cultural situation differ to yours, and while you may sincerely hope for her to have "self-sovereignty" as you see it, your architectural imposition actually denies her it.