Earlier quoted context omitted.
The Shura uses double-shot keycaps, where the legends are a different colored plastic whereas earlier TEX models used UV printed or laser etched keycaps. TEX’s older method is common to a lot of keyboard manufacturers and is prone to wear like you’ve seen. By contrast double-shot keys will get shiny, but their legends will always be legible no matter how many years they’re used.
Those keycaps are doubleshot ABS, though, and ABS is widely considered to be an inferior material compared to PBT. At that price, you would expect the latter.
Most of the affordable PBT caps I’ve seen have been dyesub (which can be very durable if done well) or PBT-ABS blend doubleshot.