A common expression is "to make a sound decision". "To make a well-calibrated decision" works, although it clunky and, as David says, no common.

It is not common, but English is flexible you can use whatever adjective you need to fit the context or situation. So you can use it but without knowing the full context, i.e the full text from where it was or is used; it will be difficult to suggest an alternative adjective. If I personally were to use well-calibrated to describe a decision. I would say the decision was purposefully/ blatantly/ wilfully / knowingly / cruelly / brazenly / well-calibrated and aimed at causing the most --> x TO --> y.

I would say "well calculated" depending on what you mean. A well calculated decision is one that is : sly, devious, risky. "Well calibrated" sounds odd to me. I would understand it. British English instead of American???

"Decision" being "well-calibrated" can indeed make sense depending on the context. "Well-calibrated" typically implies that something is accurately set or adjusted according to a standard or requirement. In the context of decision-making, it could mean that the decision is well-informed, balanced, and aligned with the circumstances or objectives at hand. For instance, you might say: "The decision was well-calibrated, taking into account both short-term gains and long-term consequences." However, whether it sounds natural or not could depend on the specific context in which you're using it. If you're unsure, you might want to provide more details about the decision and the situation to get more targeted feedback.

It's more common to use "well thought" instead of "well calibrated."