If the claim that "Suicide is not a quantitative measure of mental health" means that such large fluctuations in the suicide numbers across many jurisdictions with differing underlying rates can't be used to inform any opinions about the impacts of the pandemic on mental health then I emphatically disagree.

I don't know who said you can measure mental health without accounting for the environment, I never made that claim! I literally said "I don't think it is "safe to say" much of anything about suicide rates or individual motivations, it is a complex issue."