Maybe I am giving away too much, but part of my edge is that I am trading against others who think exactly that: that psychology is "overrated."
You’re one of the few who gets it.
Having a methodology with a positive expectancy is important (one cannot make money consistently without an edge), there is no question about it.
However, when it comes to consistent, flawless execution, then the psychology / mindset takes over, and most traders start to fall apart because our brains are not wired for efficient decision making and for dealing with uncertainty.
The above does not play such a big role with small accounts, but the bigger the account and the faster the TFs, the more important psychology / mindset becomes. To consistently execute without mistakes and hesitation, we need to “train” our brain for peak performance and to master ourselves because when trading we're actually asking our brain to do something that is diametrically designed against.
Most of us are actually blind to our own issues, and for majority of people this becomes major obstacle, and they try to overcome it by seeking “holy grail”. (Transferring their issues onto the market). Been there, done that myself.
People just want to make heaps of money, and believe that buy/sell signals is the only edge they need. I used to be the same. It took me years to finally accept that self-mastery is a huge edge in the market.
Before the realization, I always wrongly assumed that once I become profitable, then I’ll have a look at what the mindset / psychology “nonsense” is all about. Ironically, only after I got my shit together did things begin to fall into place.
These days, the more people disagree with me on the importance of peak performance mindset / psychology, the more confirmation it gives me that we really “trade our beliefs”. Understanding this, and working on and maintaining peak performance mindset is huge edge over those traders who only focus on TA.