Most files labeled "Euro Truck Simulator 2 PSP" are actually mods of other existing games. Modders often take older PSP games like 18 Wheels of Steel: American Long Haul (which did have a PSP version) or Road to Hell and reskin them with truck models and menus to look like ETS2. While they might look somewhat similar, they are not the real game. You won't find the same map detail, physics, or truck customization as the PC version.
If you are looking for legitimate PC repacks to save space, the Steam Community recommends never repacking base .scs files yourself, as it can break game updates. 🛣️ Legitimate Ways to Play euro truck simulator 2 psp iso file download repack
: There is a fan-made "Virtual Dashboard" project that allows you to use a physical PSP as a secondary telemetry screen for the PC version of ETS2 via custom firmware (CFW). Most files labeled "Euro Truck Simulator 2 PSP"