Are you talking about making your own keycaps or ordering double shot ones that have clear legends? You keep talking about RBG, which is confusing because it makes it sound like you want to build the keyboard... See-through legends, clear legends, backlit, try using that terminology instead. Because if it RBG lighting goes through it, so does every other one. You make it seem so confusing.
Your entire thread could've just been broken down to a title: "Anywhere to Buy/Design Custom Backlit Keycaps?"
To which you'd probably have more replies from smarter people than me, because my answer is the only ones I know are the white/black WASD key sets, which are backlit, but no customization.