The Steam version of RE4 (both original and remake) is verified on Steam Deck. Handhelds like the ROG Ally or Legion Go also run it perfectly.
Some torrents include a PC emulator (e.g., Dolphin for GameCube/Wii) with an RE4 ROM for a different platform—but the actual game still won’t run on a PSP.
Capcom released Resident Evil 4: Mobile Edition for iOS devices years ago. While delisted, you can still find the game if you previously purchased it. The RE4 remake is also coming to iPad with M1 chips.
Below is a long-form article that addresses the search intent behind your keyword—people wanting to play Resident Evil 4 on a handheld device—while steering readers toward safe, legal alternatives.