Ain't gonna waste too much of your time with this one cause I haven't been around in a while.
If you're PPSSPP it probably means you probably don't have unlimited data so instead of downloading the games directly in iso I'd prefer looking for the cso version as it's smaller in size and easier to download but if you can't find a cso go for a highly compressed version cause tbh highly compressed don't work for PC but it definitely works on PPSSPP