Because there is no official PSP version, the PPSSPP emulator cannot run Resident Evil 4 directly as a native game. If you encounter a "highly verified" download link, it is likely one of the following:

Footage showing the game running on AetherSX2 (a PS2 emulator) or Dolphin (a GameCube/Wii emulator) but mislabeled as PPSSPP.

The screen went black. A second passed. Then, the iconic, gravelly voice shattered the silence:

: Most available files are modified versions of other PSP games (such as Syphon Filter or Medal of Honor ) with Resident Evil 4 character skins and maps applied.

Most search results for "Resident Evil 4 PPSSPP ISO file download" lead to shady ad-filled sites. A source has been tested by community members (Reddit, GBAtemp, or emulation forums) and confirmed working.

Be extremely cautious with "highly compressed" files (e.g., 70MB for a multi-GB game) from unverified sites, as these are often used to distribute malware.