OP calls it a rant - but to my mind, a totally justified one.

It’s one thing to be troubled in this way by the wholly inconsiderate behaviour of fellow passengers ; and another to have your appeals for constructive support from CC totally ignored. I would have felt similarly aggrieved.

I would most likely have taken myself down to the near-empty WT ; and if subsequently challenged by CC, explain that I value the ability to enjoy my flight within a reasonably calm environment, hence my choice of cabin when booking. “Could you please help me by taking action to quell the disturbance so that I can then return to my original seat ?”