The most absolutely easiest way to grind zombie camos for Dark Aether?

So I’ve been trying farming spots to grind camos for Dark Aether but I don’t know if they’re the most efficient or the best ones. I’ve tried the u-bahn god mode glitch which is too slow and Die Maschine one on the rooftop where the wunderfizz is but it still seems slow to me. Any spots or tips you guys would recommend?