That heritability doesn't cover all genetic factors. E.g. out of 100% of IQ variation 50% might be inherited, but that doesn't say that the rest is nurture, rig

That heritability doesn't cover all genetic factors. E.g. out of 100% of IQ variation 50% might be inherited, but that doesn't say that the rest is nurture, right? It can still have a huge factor of genetic lottery. E.g. isn't heritability the mean of the genetic effects, but there's also the rest of the distribution (std. dev)?