Power level has nothing to do with it. Either everything is in proportion to work correctly, or it is not. Rayon might last longer, if true that will be true for most or all correct setups. It might handle slightly more power, but if so then the same setting is simply wrong for cotton.
If you push your vape to a slight burning on every drag, it will get worse and worse. If you then turn it down or whatever it might recover. If you burnt it only a little, on isolated incidents, it probably will. By "it" I mean you burn the wick but also juice. With a RDA there's also the issue of dripping. One good mistake, forget to drip, is so nasty and if you forget twice you can even set the wick on fire. I strongly recommend using Temperature Control (SS316 wire and correct settings).
The power and setup must work together with technique. To vape at those power levels requires pulling in a lot of air. Without TC especially you need to be aware of what the vape is doing until you learn what works.
Like was said, clean and rewick and try again, less power or more careful about dripping. Or change coils or wicking techniques if that seems it might work better for you. It's cheap!