PSA: It's now possible to run homebrew on an unmodded PlayStation 2 using only a burned DVD, using this hack: https://cturt.github.io/freedvdboot.html
Using that, I was able to rescue everything off my 15 year old memory card and convert it to (the pretty-good-at-this-point emulator) PCSX2's memory card format. It's a comfort to know that all these old adventures won't be lost to time.