It's called hormesis. Yes, there is a range beyond which further stress causes permanent and serious damage, but within the hormetic range "adversity" is basically the proximate cause of growth.
Stress impact also varies per individual biological differences.
According to Sapolsky's lecture on depression [1], a stressful childhood experience is 30x more likely to cause depression in individuals with a particular serotonin-related gene variant.
No. [1] The context of the whole conversation is traumatic relationships. If anything you are talking about eustress - and traumatic relationships are not beneficial and do not "make you stronger" [2].