Autism

Yep. It's maddening. It's also a skill, same as anything else. It requires regular exercise. I hope this doesn't sound condescending; it's how I had to walk myself through these kinds of situations in the early days.

For trivial decisions like what to get for dinner, flip a coin to determine. If you feel yourself regretting the coin flip, just do the other choice. It's what you subconsciously wanted more.

For important decisions, start with the knowledge that you will likely never know everything. Then, realize that beyond a certain level of seriousness, there is rarely an ideal outcome; there are only outcomes whose drawbacks you can live with or work around.

From there, curate the info that will help you. Break available info into pieces. Write shit down or draw pictures. Put together some questions. Those are your known unknowns. The more you do this kind of stuff, the more of a feel you'll have for how these known unknowns will work out. But, even at the beginning, thinking through these questions will give you more confidence.

Spend a little time working through places where unknown unknowns will trip you up. A good way to do this is to imagine you've made the decision, and asking yourself what you'll be regretting next week. Another good thing is to think back to similar decisions made by others, and thinking about what caused issues for them. Again, the more you do this, the more of a feel you'll have for how things will go.

Show your work with your decision. "I've assumed A and am recommending Decision D. We'll have extra work around X and Y, but those can be mitigated far more than the consequences for Decision E."

Yeah it's not perfect and you'll make mistakes, but you'll develop more instinct around what's available to work with.