
I see you’ve chosen to go with Option 3, at least for now. (Previous comment for reference.)
To be perfectly frank, it sounds like you’re already half-assing your job and maliciously complying. Think about it: you do only the exact amount and type of work as specified in your job description, you actively resist being given additional work even when you aren’t currently doing anything, you don’t offer help to coworkers when you have the ability and they have a need, and you openly flaunt these facts by using your downtime (even when not officially on a pause) to write poetry or otherwise not do work in locations where your coworkers and manager can see you doing it.
If malicious compliance and the bare minimum are your goal, then congratulations! You’ve accomplished your objective.

What you consider to be “above and beyond” is what others consider to be a standard part of any role. Other comments on other posts you’ve made have said the same thing: a general “additional duties as assigned” clause is very normal, and nothing you’ve said has given the impression that what you’re being asked to do is atypical.
Your manager considers helping out your coworkers to be part of your base responsibilities. This is a normal expectation. If it’s one that you have no desire to meet, then your best bet is to find a new job. The problem there - as both I and others have pointed out - is that any other job you find will likely have this same expectation.
I was in your shoes about five years ago. I felt it was completely unfair, I tried other roles in an attempt to find a job where it wasn’t expected, I asked coworkers how it was possible that such a thing was normal… I get it. It’s not fun. But living at this time and in this place under these conditions - it’s normal. I personally chose to suck it up and deal with it, and ultimately I came around to understanding that it wasn’t as bad as I was making it out to be. It’s not perfect - I’m not saying that - but part of having a job is working with other people, and that includes the give-and-take of what you’re experiencing right now.
If you honestly, truly can’t bring yourself to work under these circumstances, you might want to change careers. Contract and gig work could potentially give you the strict adherence to tasks that you’re looking for, but it may come at the cost of pay, benefits, or difficulty in finding work. Starting your own business will at least mean all the work you do directly benefits you, but that again comes with its own set of risks.
Final thought:
Being employed so you don’t end up homeless. Nothing grander or more meaningful than that. You need a job, so you’re doing what it takes to keep your job. Same as the rest of us.