Expose setting fields to other scripts as properties

[MarcusOtter]

Is your feature request related to a problem? Please describe.
Many fields in the internal logic are private readonly and have to be initialized in the constructor. This works fine unless values should be changed dynamically. It also falls short when there are many variables. An example is the ErrorHandler which has at least 5 settings (_jsonSerializerOptions, _firstValidDate, _lastValidDate, 2 unnamed constants in CountIsInRange()). When implementing the count error handling, I just ignored the extensibility and set 0 and 100 as constants (bad).

Describe the feature you'd like
Turn most of these fields into properties that can be changed from any class. There's no need to be overprotective of these, there are good reasons for other classes to change them.