Is a "win rate" really such a thing in crypto trading? From what I know a win rate is something being used by those odd pickers in gambling but not in trading because there is no such thing as a win rate for a trader since the market is to volatile to guarantee such trader being accurate in the market. Risk management is also barely used in the trading lingo but I believ what you are trying to say when risk management is involved is the cutting of losses of a trader to the bare minimum. In your example where the trader have lost 15% of his capital this can be something mitigated or avoided if the trader react way earlier or has a back up plan/ exit strategy when the target price failed to hold, maybe losing only up to 5%  is what you will be looking for if you are trying to manage your risk.