Note that the ‘implemented in 2026’ list did not claim to separate these storage classes, only that the path is selecteable.
This ‘unmanaged media workflow’ enhancement from @cnoellert is marked as implemented, but it may be a question of how you interpret it.
Was the intent to have renders in user space, or was the intent to separate volatile from needed?
Also note this still open enhancement request to ‘rebuild MIO’ files if lost.