Since you cannot download RE6 for PPSSPP, use this guide to set up the emulator for the actual PSP Resident Evil games (like the Silent Hill or Obscure titles, or fan-made RE mods).
Resident Evil 6 did not release on PS2 either. This is another dead end. Resident Evil 6 Ppsspp Zip File Download Android
These run flawlessly on PPSSPP for Android. You’ll need to find the PSX2PSP converted EBOOT files (usually zipped). They offer true survival horror on your phone. Since you cannot download RE6 for PPSSPP, use