All of which have either been deemed legal or are being investigated by the IRS and maybe the FBI. A common reason to publicly release tax returns is to find dirt but a good public reason is to allow voters to see the true character of the person asking to be President. Same for medical and psychological evaluations along with monthly drug tests.
FWIW, not only would Trump probably not have been elected President in 2016 if all these records were known at the time, but neither would have Hillary then nor Biden now.