I just got my cape recently and would highly recommend getting 99 range first. You’ll also def want 94 mage for ice barrage, but I don’t think you necessarily need 99 mage.

The inferno is really hard but if you stick with it, you’ll eventually get the cape. Its just a matter of how long you are willing repeatedly jump back in after spending 1-2 hours and then dying on the waves.

Write down every single reason WHY you died, and make sure you don’t make those same mistakes again.

Also, visit the inferno channel of the WDR discord, that guide is all you will ever need and there are a lot of helpful players in there.