You are simply moving goalposts. My point is that I disagree with your idea of making sign language universal or formally making even a rudimentary universal sign language. I think that would be impossible if you understand language itself. I gave you resources so you could educate yourself about why.
Yes, the sign for eating would look different in China vs Ethiopia vs the US. So what sign are you going to have it be to imitate eating in your formal language? Do you see how this can perpetuate colonization?