The original boundaries were drawn by the British to create the fiction of a Jewish state, although the designated territory was polyglot from the start. The fiction could only be realized with the Nakba when the vast majority of “Arabs” were forcibly expelled.

Ah, the assumption that of course a particular ethnic or religious group would have criminally purged another group even if they had been left alone and not attacked. That belief undermines so many efforts to bring about peace in so many places....perhaps even in this region, when Jews engage in that belief when considering what a Palestinian majority might do to them? However, we'll never know if that would have been true in 1947-1948. The Jews were never given a chance to demonstrate what would happen if the partition plan had been allowed to move forward, since Egypt and Jordan attacked basically immediately.

You’re conveniently ignoring the new Israeli state seizure of “Arab” lands as well.

Not at all. I'm looking at the counterfactual of what might have happened if Egypt and Jordan had refrained from waging war to wipe out the Jewish state at its birth - if something like the India-Pakistan partition had been allowed to proceed, which despite the horrific trauma (which should never be minimized) still resulted in an uneasy but stable peace rather than eight decades of open conflict.