The problem is how many plot holes surround sphene. Take the part of tural that got absorbed by the barrier, why does sphene welcome them and make them into alexandrian citizens creating more endless for herself when she could have forcibly harvested them to power the endless like she planned for the rest of tural
The lack of “looking for an alternative solutions” is built on sphenes lack of agency given her programming, but then they aren’t even consistent with it