Thank you for taking the time to give an in depth answer.
So if I understand well, the only thing real to you is your internal state. Your internal state depends on you doing enjoyable things and more precisely, sustainable source of joy.
Correct me if I’m wrong, but, since you make a distinction between “joyful things” and “sustainable joyful things” couldn’t we say that; doing “sustainable joyful things” gives meaning to your life.
#plebchain