If all lives are happening at the same time, as reflected in Far Journeys, then I don’t think there is anything that can be done at EOL to terminate the reincarnation process prematurely.
I kinda see it like an octopus with the head and body being the soul and each tentacle being an individual life/personality. One tentacle can’t prevent the existence of another tentacle. It can only improve its own existence by working to experience itself as part of the whole instead of separate, which causes suffering.