I think I know what's wrong.
The readme file is incorrect, specifically "Part 2"
Put the Part 2 files into "update\x64\dlcpacks\mppatchesng\dlc.rpf\x64\models\cdimages\mppatches.rpf\player_zero
The readme is missing that final folder in the instructions. "player_zero".
Since you said you followed the readme exactly, that would mean you placed the files directly into mppatches.rpf, not the player_zero folder. You can blame the mod author for the misleading instructions. But yeah, I just downloaded that mod and put the files into the correct folder as stated above and the mod works perfectly. So it should work.