RX480 will outperform GTX1060 in some games and overall there is negligible difference, so I wouldn't recommend changing, you really want to be looking at an RTX2060/2070 if you are going to upgrade. Do you know what make and model of PSU you have? There is a huge variability in quality and you don't want to be sinking £400-500 on a new GPU if you're existing PSU isn't up to the job and prebuilts often have cheaper, poor quality PSUs so I would definitely recommend checking.