When I say breakouts are 50/50 I am talking about placing a buy / sell order above and below the range and waiting for one to trigger and using the other as your stop.
If you trade either the first pullback after the breakout , or the breakout fails and you trade the failure then you are starting to manage your risk / reward and as a crude rule of thumb , once you get good at identyfying these 2 patterns then probability is in the region of 70/30 at worst.
But most imprtant thing is the context in which the range develops , and how long it has been in place , for example if you have had a strong move up , then the market pulls back , breaks a trendline then moves back up to retest the high , forms a range then a breakout to the upside fails , then you have a 90% plus probability of a succesful trade to the downside.
So can't give you a simple answer , but if you have the discipline to only trade first pullbacks and failures you would have a very profitable trading plan, i.e. a 2:1 R/R on a 70% probability trade.
Find the patterns that appeal, put the hours in to understand all their nuances , and within time you will just know when they are going to work and when you need to sit on your hands.