Useful feedback has one or both of two characteristics –
(1) The giver hones into the exact trade-offs that the presenter/receiver is struggling with and adds insightful perspective that helps them navigate it
(2) The giver adds a new dimension that the receiver didn’t consider and thus changes how the receiver views the problem
And, generalized truths/”principles” (often misused – more on this another day) tend to fall into the true-but-useless category.