To get all DLC for Tekken Tag Tournament 2 (TTT2) working on the RPCS3 emulator, you need to handle two main things: updating the game to the latest version and using a specific save file. Unlike modern games where DLC is a separate purchase, TTT2's characters were mostly added via free game updates. 1. Update the Game (The Easiest Method)
The most reliable way to access the full roster is to use a pre-existing save file where the DLC has already been registered. You can find these on the RPCS3 Wiki or community forums like The Update & Patch Method: tekken tag tournament 2 rpcs3 dlc
.pkg format or as extracted folders (often labeled BLUS31011-DLC or similar).