I do think you are unfair to yourself and me when you state nothing matters due to death, but that things matter while alive. Either they matter, or they don't, but I do understand what you mean since your argument is not in a strictly "logical debate" fashion, but one that you have with yourself and becomes rather confusing out in the open.
Anyways as for you post, that is why I put "unless pushed in one direction." in mine. Personally I take the stoics's viewpoint of suicide, as Epictetus put it “Has someone made smoke in the house? If it is moderate, I’ll stay. If too much, I exit. For you must always remember and hold fast to this, that the door is open.”. There is at the end of the day only a subjective interpretation of reality, which decides if living is worthwhile or not. If you believe life to merely be suffering and nothing else, while also believing that suffering worthy enough for suicide, then exit as soon as you can. That is the only proper response, and there is nothing wrong with that unless you believe in magical gods writing down rules against suicide.
Perhaps this sounds like a very simple answer, or even self evident that if you believe life not to be worth living you would not live. My answer to that, is simply to say that is why it is probably true and worth thinking about. After all I cannot magically convince you that life is not suffering, nor would I since it very well might be. All that "matters" is if you believe it to be, and what action you will take afterwards.