Not sure how to tag a user, but rvbomally made a map of such a scenario:
Interesting that those books also discuss zones of occupation in the Japanese-held territories of China, implying that the decision to return those areas to Chinese rule hadn't been made yet. They also note that even in the pursuit of a zone of occupation in Japan, Stalin was not at all...
www.alternatehistory.com
Not super realistic with areas of control, but foreign backers seem reasonable. This map takes the stance that Iran will get bogged down into a long struggle. Even if Iran stays only in areas closer to its border like Herat, Farah, and Zaranj and supports proxies, what's the end goal? With Taliban likely holding firm in Pashtun areas unless the US invades, and many countries and groups becoming more and more impatient with Iran like they are with Turkey and its actions in Syria, would there be any advantage in staying and to keep up spending to maintain control over their territory?