Does being less directional psychologically make you more successful in trading ?

From my 1 year of forward-testing results, I believe yes, especially in terms of peak to valley drawdowns and taking stops decisively.
how so? I used to hold SDS or SSO ETFs position on one side. either long or short at a time.

Due to minimum holding period reasons, I had to hold both simultaneously. I tend to have a much more stable/balanced pshychology, even when my net notional directional exposure is about the same.

Intuitively, it makes no sense, but psychologically it does at least in my trading. I am not sure if it's because I felt 'less' wrong when a trend turns since one side is always green in P/L and in turn you were able to get out of the wrong side easier in relative terms.

Just wondering if anyone did similar practices in futures since the psychological element is even more important in futures trading than equities/ETF because of the overly leveraged P/L swings ?

I think psychological challenge is a major part only if a trader trades manually.
Trading systematically using algo would take the psychological challenge completely out and you will realize there is a different challenge altogether unrelated to psychology.
Then you may realize even having elite-level psychology may not be enough.
I don't know about you but this applies to me.