To me the solution to this problem is to not rely too much on raw consequentialism for dealing with real-life situation. Because I know my model of the world is in perfect, that I lack computing power to track all the consequences of an action and evaluate their utility, because I don't even know my own utility function precisely.

So I'm trying to devise ethical rules that come partly from consequentialism, but also taking into consideration lessons learned from history, both my own personal experience and humanity's history. And those rules for example say I should not kill someone, even if I think it'll save 10 lives, because usually when you do that, either you kill the person and fail to save the 10 others, or you failed to think to a way to save the 10 without killing one, or you create far-reaching consequences that'll at the end cost more than the 10 saved lives (for example, breaking the "don't kill" taboo, and leading for people to follow your example even in cases when they'll fail to save the 10 persons). That's less optimal than using consequentialism wisely - but also much less error-prone, at least to me, than trying to wield a dangerous tool that I'm not smart/competent enough to wield.

That's quite similar to the way we can't use QM and GR to make planes, but we use simpler, "higher-level" laws, which are not as precise, but much more computable, and good enough for our needs. I acknowledge the core of physics is QM and GR, and the rest are just approximations, but we use the approximations because we can't wield raw QM and GR for most daily life problems. And I acknowledge consequentialism to be the core of ethics, but I do think we need approximations, because neither can we wield directly consequentialism in real life.