You are either optimizing for the wrong thing, or don't know what you want.
If want to be as frequently correct as possible, then your "negativity" is strength. The issue with this strategy is that it will prevent you from engaging with the real world the way that positively thinking people do. You will take less chances, since you realize the probabilities of failure are so big.
Positively thinking people are kind of delusional. They try to ignore the ugliness of reality and focus on the positive side of things. However they are the risk takers. They might fail a lot but at the end of the day they are the ones that succeed in changing reality for the better.
Both ways of thinking have their advantages and their drawbacks. As far as I can tell, it really depends on the type of person that you are.
You can also stay realistic, while being neither too negative nor too positive.
You can step back and identify the negatives and the positives of a circumstance or plan, weigh them (quite literally in a table for anything complex, it really helps), and set a course of action based on that. Then you price in the risks of negative consequences, while aiming for potential positive outcomes in the future.
Otherwise, being super negative and not trying to change one's situation sounds like distress, and seeing only the positives to a potential course of action sounds like folly and risky planning.
I also think that this can be trained. There were times when I was really negative about everything, but I developed a habit to notice when I was experiencing this negativity, and try to identify positives too, to balance things out. It did give me a lot more agency.
"Realistic" is not a middle point between "Negative" and "Positive". If you want to have a model of reality that is as close to truth, it would fall significantly closer to "Negative". (https://en.wikipedia.org/wiki/Depressive_realism)
However there are strategies that both ways of thinking can adopt to improve their experience / performance in the real world.
Optimistic people can try to see "both side of the coins" and not miss underwater rocks.
Pessimistic people can adopt a defensive strategy where they minimize risk to the point that they are willing to take it.
Two side notes: You can be smart about it in both situations. Also in both cases you should take out the emotional toll.
I agree with your side notes, though I would add that depressive realism is a hypothesis in psychology that is challenged by other academics, rather than a settled fact.
From your link, "Depressive realism is the hypothesis [...] that depressed individuals make more realistic inferences than non-depressed individuals [...] [Critics of depressive realism argue that] depressed individuals are thought to have a negative cognitive bias that results in recurrent, negative automatic thoughts, maladaptive behaviors, and dysfunctional world beliefs."
The critics would say that depressed people have unrealistic world views, which causes depressive symptoms. This matches with my own personal experience (e.g. when I felt convinced I could never be happy for a while after I got dismissed at my job, which was convincing at the time but turned out to be totally wrong).
However, I do think you can be pessimistic without the emotional toll as you say; but that doesn't sound like a depressed person, if this person can still excel at motivation and doing hard things.
My bottom line is: I just don't believe in the depressive realism hypothesis just to focus on the first bit, but I agree with the take on pessimistic realism.
Being negative is probably statistically correct. But I find it to be more or less a useless model.
Most things to be negative about are not actionable. Maybe in the old days, you could be stressed out about a tiger in the area or an upcoming war and it'll literally save lives. But today, you can be stressed out about Trump or COVID-19 and it'll probably change nothing. In fact, COVID-19 impact has been worst where people are most panicked about it.
There's also where it becomes grief - denial, anger, bargaining, depression. This is not realistic nor useful.
Optimism is a filter. You don't purposely blind yourself; you focus on what you can have a lot of impact on. You can turn the filter on and off (provided it wasn't installed stupidly in the first place).
>But today, you can be stressed out about Trump or COVID-19
Stress has nothing to do with it. I can agree that stress rarely has application in our modern day lives. You can be a stress-free negative thinker and also it is possible to be a stressed positive thinker. (positive thinkers fail more, it is possible for that to have an impact on people)
Again, none of these are necessities to be a negative thinker.
>Most things to be negative about are not actionable.
That is correct. It is undeniable that negative people are not very effective in our world. Even further - all negative philosophies and religions (Buddhism, stoicism, western pessimism, etc.) focus people on enlightenment and perfecting the person's inner world. A monk has zero interest in changing the world at scale.
However it seems to me that there are certain practicalities about negative thinking. You can be smart with it.
If you take it at face value - negative thinking is kind of a superpower, it allows you to think what can possibly go wrong and frequently you more cautious than you had to be. You can use that to minimize risks and if successful - you can take actions, because the risk is no longer that high.
You are completely right here, negativity definitely helps finding issues. How does negativity help fixing issues? Can you trust a certain issue to be fixed?
If want to be as frequently correct as possible, then your "negativity" is strength. The issue with this strategy is that it will prevent you from engaging with the real world the way that positively thinking people do. You will take less chances, since you realize the probabilities of failure are so big.
Positively thinking people are kind of delusional. They try to ignore the ugliness of reality and focus on the positive side of things. However they are the risk takers. They might fail a lot but at the end of the day they are the ones that succeed in changing reality for the better.
Both ways of thinking have their advantages and their drawbacks. As far as I can tell, it really depends on the type of person that you are.