If you want to play a western-themed game on your PSP, you can check out:
Many sites claiming to offer a "highly compressed" RDR2 ISO for PSP are deceptive . Red Dead Redemption 2 Psp Iso Download
– Sites offering fake PSP ISOs for non-existent games often contain malware, malicious ads, or corrupted files. If you want to play a western-themed game
The short answer is no, it's not officially possible to download Red Dead Redemption 2 as a PSP ISO because the game was never developed or released for the PSP platform. The PSP, being a handheld console with limited hardware capabilities compared to modern gaming systems, would not have been able to handle the game's complex graphics and vast open-world gameplay. Red Dead Redemption 2 Psp Iso Download