You are correct in that most of the callback methods orient around the level 1 banner/barrier elements. There is, however, one callback for the Options Dialog that is triggered after an already provided consent is changed. This means that the user consents somehow, they go back to the Options Dialog to change their consent preferences, they save their changes, and this callback runs:
window.evidon.consentChangedCallback = function () {
// custom code
}
Additionally, this callback can take three optional paramaters: categories, vendors, cookies. This would look like the below:
window.evidon.consentChangedCallback = function (categories, vendors, cookies) {
// custom code
}