For some context, I am a teacher. My boss doesn't compromise ever, won't listen to any of my arguments and will just keep giving me more work. Meanwhile, he leaves work dead on time and plays Candy Crush in the office. These are the most common scenarios.

A. Boss asks me to run an unpaid club every week with my students (on top of 2 free lessons every week). I say I can't do it because I have other commitments. He asks 'like what?"... I say X, Y and Z, I already do A, B and C and I ask if the club is necessary and if we can split the workload - he'll ask why can I not do it all...and we're back at the start...

...truth is I just don't want to be the only person staying after work and not getting paid for it; I want to have a life outside of a job.

B. Boss gives me extra work to do. I say I can't do it or ask for an extension as I have other things to do. He'll tell me to be more productive so that I can finish the work within my working hours. I will literally show him everything I have to do, how little frees I have to complete the work and he'll me to be more productive so I can squeeze in the additional work (which is impossible as on top of my work, I am doing the work he is meant to do ... and he is getting paid thrice as much as I am) or will just say 'well, that's teaching for you"

(note that the workplace is just as shit and I can't report him so i need a solution as I look for a new job)