Downloading PS2 game ISOs/ROMs without owning the original disc is piracy. However, you can legally play PS2 games on PC via several legitimate avenues:
Rip your legally owned PS2 discs to ISO files using your PC's DVD drive. This is the only legal way to use an emulator.
Stream a library of PS2 classics (e.g., God of War, Ratchet & Clank) to PC via the app. Requires an active subscription.
Many classics have native PC versions available for purchase:
Buy these on Steam, GOG, or the Epic Games Store. Always verify system requirements before purchasing.