Even if a full emulator were released tomorrow, there are serious caveats:
If you are looking to explore this further, I can help you with: open-source repositories on GitHub to study the code. Understanding the legal history of Blizzard vs. private server projects (like Nostalrius Explaining the packet sniffing techniques used to reverse-engineer network protocols. Which of these areas would you like to diablo 4 server emulator work
Diablo is up StatusGator reports that Diablo is currently operational. StatusGator Even if a full emulator were released tomorrow,
However, there are also risks involved:
Emulation groups must essentially reverse-engineer the entire game to trick the local client into thinking it is talking to Blizzard's official infrastructure. This massive process involves several highly complex steps: diablo 4 server emulator work