Both the game and the DLCs are still working as of 4/4/2022 (Yes I'm still playing this) Thanks to
Douglas Oliveira for helping me figure it out. Here's how:
-I'm running on HEN
-Download files, and extract them.
-Black Ops needs to be in the GAMES folder on the PS3 HDD. I don't think it works for the disc version
-Everything from the DLC folder (The DLCs, update, and DLC fix) needs to be on the root of a FAT32 USB stick, meaning the USB should be formatted to FAT32 and all of the individual files should be at the root of the USB and not in a folder.
-Plug the USB into the right USB port of the PS3 (the one closer to the disc/ power button)
-Enable HEN on your PS3, then go to Package Manager>Install Files>Standard
-Install the DLCs one by one
-Install the update
-Install the DLC fix
-Restart the PS3 and the maps will be there. I use mmCM (Multiman), so I enable HEN, go to Multiman, Select black ops, then it takes me to the main screen and I select black ops again.