This is great insight. I'd like to offer a slight alternative for "You just kind of have to minimize the wrongness".

I think a CTO should have several mental models for making decisions. Minimizing wrongness is just one.

Some examples:

- Is this decision reversible?

- Does this choice allow my team to grow technically?

- Will this matter a year from now?

- Is this something I can buy instead of build?

- Is this a core competency that we should invest heavily in?

- Does this decision go against the company or your personal values?

- Is quick and dirty good enough for this?

There are several ways to orient the problem to help make a decision. But the OP is totally correct, this decisions will usually be made without all the data and with a lot of people looking at your decision.