If it makes you feel any better compatibility is probably pretty mixed. Last I checked the PS2 memcard slot doesn’t have enough bandwidth to load all games reliably.

140ish gigs for the kiwix copy

Yeah, wish they were a bit more upfront about that. In their defense it is in the FAQ and somewhere at the bottom of the “about this project” page. Battery is also an add on unless you want to source your own.

“Steam Replay” it’s like Spotify Wrapped for Steam playtime/achievements.