The search for a "Resident Evil 4 PPSSPP Android ISO" is based on a technical impossibility. The game does not exist for the PSP platform. Users engaging with websites offering this file are exposing themselves to data theft, malware, and phishing scams. The recommended course of action is to purchase the official mobile port from the Google Play Store or use a legitimate PlayStation 2/GameCube emulator with legally obtained game files.
Once you have the highly compressed ISO file on your phone, follow these steps: The search for a "Resident Evil 4 PPSSPP
If you want, I can: