A PhD has basically zero value (probably net negative) unless you want to go in to academia for the rest of your life and retire as the head of department at an

A PhD has basically zero value (probably net negative) unless you want to go in to academia for the rest of your life and retire as the head of department at an Iowa community college, so double check you really want to do that and have that kind of life? You need to double check your mental/emotional and physical health. Are you getting sleep? What are your serum vitamin D levels? Do you wake up and run a 5k every morning? Have you travelled to a new or slightly dangerous place on the opposite side of the world in the last 6-12 months to reset your beliefs about the world? - These are the type of questions you need to be asking. When you have this stuff figured out and you feel alive, motivation will not be an issue.