I know the point you’re driving at, but if you’re building a theme park land based around a specific culture (and any major eastern Asian city is intricately tied to that country’s culture), it’s vital that you don’t elements from a painful history that is deeply offensive to that city (and the country you’re ostensibly celebrating). San Francisco never militarily occupied LA, tortured its citizens, and try to eliminate its culture. Japan DID do that to Korea. And it’s not ancient history—the occupation ended in 1945.
You may not bat an eye at saying at referring to “Kaiju” in Pacific Rim as it relates to Seoul. Other Americans may not. Koreans absolutely would, especially when this idea already shoe-horns an American franchise (Pacific Rim - which only made $30m across both films in Korea) and an American movie (KPop Demon Hunters) owned by a Japanese company (Sony).
The histories of East Asian countries are complex and the hurt that results from that history runs bone deep. If you want a Seoul area, I recommend you find actual Korean properties to populate it with. If you prefer Japanese IPs, build Tokyo. If you like both, then build BOTH. Suggesting a hodgepodge of these ideas into an approximation of any specific location from those countries creates a perception that they’re basically interchangeable. They’re absolutely not.