You should not use steroids until you reach the figure of 15% BF. First of all, the higher the BF, the higher the chances of suffering certain side effects. Secondly, the high BF% is usually an indicator that your diet is not on point, or there is something wrong with your training. And you need to keep in mind that steroids are no magic pills - they are just a tool that makes things easier, but you still need to follow a strict diet and train hard in order to achieve results. Therefore, without those two aspects dialed in, steroids won't help.
What you may consider once things will start to move in the right direction, are SARMS, as they are good for recomping and they will not cause all the side effects that you might expect from steroids.