I used to work a non tech office job, one day it became so unbearable, I was literally falling asleep and was no longer able to bring myself to do the job at all, because of how much mental effort was required for even the smallest things. I stood up and quit.

I think it's mostly about accepting that you are the one in control. The problem of "getting yourself to do something" is poorly formulated, as though some other person was in charge of your actions that you have to convince to do what you want.

This confused conviction is the real problem. There is no other you to convince. The same you that you are bargaining with to do the thing is the same you that's doing the bargaining. You can at any moment just do it.