The game is available legally on PlayStation 4, PlayStation 5 (via backward compatibility), Xbox One, Xbox Series X/S, and PC (via Rockstar Launcher, Steam, or Epic Games Store). No legitimate “patched ISO” version exists for any platform because modern games are not distributed as ISOs.
Any "patched RDR2 PSP ISO" you find online is likely one of the following: 1. Total Conversion Mods
When you see websites offering a "Red Dead Redemption 2 PSP ISO," they are usually one of three things: