I agree & speculate that mental wellbeing has everything to do with finances. Including if a person develops a mental illness; of course there will be cases where the person is financially well off. Approximately 75% of suicides occur in low- and middle-income countries (LMICs) where rates of poverty are high.
sources:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5454768/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3431736/
https://www.cdc.gov/vitalsigns/suicide/index.html