Manually validating the values using data annotations

Question

I have a model something like this.

public class Feedback
{
public string FeedbackType { get; set; }
[AntiXss]
public string FeedbackMessage { get; set; }
}

For example, When I post the below message from FE using a 'TextArea' field

Hello (This is in first line)

This is awesome(This is in second line)

When this value gets bound to the model, it is like

'Hello\nThis is awesome'

As a result AntiXss attribute does not pass the validation (because of \n).

What I want to achieve =>

1. Remove the data annotation from model
2. Encode \n to something else in the controller
3. Manually call the AntiXss annotation in the controller so that the value gets validated against cross side scripting other than '\n'.

Something like this.

ValidateMessage(feedbackMessage, AntiXssAttribute)

So basically I need a code which can accept the name of the attribute and the value to be validated, then finally returns me if the value is correct.

I have already tried the below code to avoid the workaround but it does not work.

[AntiXss(allowedStrings:"\n")]