Keep in mind for the most part:
General Present Current Day, the world is split into two sides: fantasy and post apocalyptic (they’re divided like this for resources purposes), also named the “Collective Kingdoms” and “The Ruins” respectively. With a vertical split, these two parties have formed a truce and created a literal middle ground in show of co-operation. The council of Elders (fantasy) made a treaty and have proper trade negotiations with the Circle of Leaders (post apoc). Both sides work together to survive (emphasis on resources, technological advancement knowledge, and medical practices).
The Council of Elders and its people offer books on whats edible in the wild, their traditional recipes, basic spells for healing and defense, agricultural tips, and materials from wild beasts, residents have the option to visit and move to the other side, but must be taught how to use post apoc modern technologies (safety)
The Circle of Leaders offer modern medicine, food recipes, assistance in search and retrieve cases, materials from insect carcasses, the residents have the option to visit and entirely live on the other side, but must be overseen by a specialized group for training and an 80% understanding of the fantasy world and how it works/operates