Sin has already been judged at the Cross, but judgment of good and evil has not yet been concluded.
(This is one reason why sins may be forgiven in an instant, upon our facing Him through faith in Christ and confessing them to Him, while the consequences of good and evil are still to be resolved in time, but rarely in a split second as the issues of sin may be resolved in a moment’s notice.)
There remain many an issue being evaluated in the angelic domain, upon which human testing manifests His righteousness and justice.
For this reason, adversity is inevitable, in life and in death, but stress is optional through faith in Christ.
Yes sins can be instantly forgiven but the earthly effects may linger for years as you pretty much said.
GOD has used adversity throughout history to forge the character of persons as well as nations to achieve His desired outcome. Those seeming the most at peace during such relied the heaviest on GOD for deliverance and justice.
Trials of this earth are nil in comparison to the joy which awaits those who are in Christ Fold. However evil our leaders are they are defeated. But no matter how good the benevolent leaders are they too shall pass from this world as well. Some will be missed & mourned and some removal will be seen as a blessing and deliverance.