We just saw that we can make money even if the entry is totally random, assuming the exit is optimal. Does it mean that we should not care about entries at all? Of course not, a good entry will give us a better risk/reward ratio and reduce the drawdown at the same time. The point is, the exit and how we manage the trade money-wise are much, much more important than the entry itself.
Yes I do worry sometime when I was winning big in option bets that the head casino security/bouncer (SEC) may one day appear on my front door and say "we don't want you here" LOL. Just kidding, I am a small time mom & pop trader.
You read this in a book written by a vendor and it sounded good to you, and the notion took up permanent residence in your mind. The consequence is you keep repeating it over and over like a parrot. I know from a prior exchange of posts that your ability to reason is compromised. But see if you can reason that it is illogical to think that the exit is "much, much more important" than the entry.
There is no guessing here, I can spot losing traders from miles away. Winning traders are happy, positive and do not feel the need to put down their fellow traders every time.
First ask yourself this question: How do I know if my trading strategy has any predictive power ? You said you are "losing your edge", but why do you assume you have a real mathematical edge to begin with? If you don't test your system first (200 to 500 historical trades at least) then you are basically making random calls (gambling).
My little grain of sand here. Get out of losing trades at the speed of light. For years I had this problem, I clung to losing trades, I didn't want to admit that I was losing. I wanted to be right. Don't argue with the market, the market is always right, not you.