I thought it was pretty clear what I meant by “experiences” but I’ll spell it out: If some system reacts to a situation it “experiences” it at some rudimentary level. Hence the idea that simple game AI’s like pac man ghosts count for the first incomplete definition of sentience. Hell arguably anything with mass “experiences” and responds to changing situations. That’s why I gave it as an example, so the idea of what counts as rudimentary experience/choice (for the purposes of these definitions) was concrete rather than subjective as we moved deeper into iterating the definition.

You’re right that this requires you to believe that a system is actually reacting to something and that both exist instead of everything just being a figment of your imagination, but you said you already make that assumption so what’s the issue?