Your Drive Tank Is Low
Nobody explains this bit, so here it is in plain English.
Motivation is a chemical the brain has to manufacture every single day, out of an amino acid called tyrosine. Folate, B12 and B6 finish the build. Stress burns through the supply, poor sleep burns more, and modern food barely replaces it. When the tank runs low nothing dramatic happens. You still care about the work, and yet the beginning of it will not come, so you quietly decide the problem is you. Put the raw materials back and starting stops being a fight, plan or no plan.
The task is written down, the stakes are obvious, and you scroll instead. That gap between knowing and starting is the clearest sign of an empty dopamine tank, and no amount of discipline content closes it.
Four cups in and you are wired but still cannot begin. Caffeine only blocks tiredness. It never builds the chemical that makes you want to move, so the wall arrives anyway.