To put it simply... Emerald Grove.

To put it more complex: Emerald Grove is the prime spot for a BG3 Zombies map. It's got a wide range of visual elements, versatility in play style potential, an obvious main quest to complete the ritual and close off the Grove, PaP could go in the Harpy Nest, spawn could be the jail cell, the underground passage and Enclave Library connect could create a well flowed route, like... C'mon guys... Someone's GOTTA do it, but I just got into Radiant for the first time. By the time I hit that level, it'll be years.