> n individual passionately caring about all of those injustices at once will end up spamming social media with advocacy because there is not enough time to pick any one to do something with greater impact

One solution, a well-established one, is to focus on universal human rights. The rising tide will lift all boats.

Also, caring does not necessarily mean action. I do have limited time, but I've heard the above used as an excuse for most of my life, and used to subscribe to it. I've learned that while people are talking about whether and how and should you care, you can just do something. It's that easy.