I couldnt read it on the smaller version as well. Only after seeing ur bigger size I was able to tell. I tried a lot of stuff with my emotes (they are still in pending thou).
What I suggest is making the sign even a little bigger ( u have room up to the cheeks / mouth) and actually use a brighter color and make the whole font thinner. I dont know for what reason but its a lot easier readable when having a thinner font, this will also help u in dark mode.
Right now ur letters form more of a shape that is clutched together. If the letters are more seperated it will easier to be identified as a letter itself.
good luck :3