The "ISO" files you see in YouTube descriptions are almost always clever illusions. They are typically heavily modded versions of Sonic Rivals Sonic Squad
https://example.com/sonic-mania-ppSSPP-iso-rom.zip sonic mania ppsspp isoroms android download link
Searching for a link will not lead you to a standard PlayStation Portable (PSP) game file, as Sonic Mania The "ISO" files you see in YouTube descriptions
You can find the compiled homebrew files on community sites like PSX-Place or through specialized ROM sites like isoroms.com . sonic mania ppsspp isoroms android download link