how to add model errors while script injections for .net core mvc application instead of encoding

I wanted to prevent script injections using model binders, which I did using model binders but is there any way to add errors to Model instead of encoding the value, I want to display error message without sanitizing the script.

I am using .net core 3.x MVC. Below is my sample HtmlEncodeModelBinder I used

public class HtmlEncodeModelBinder : IModelBinder {
    private readonly IModelBinder _fallbackBinder;

    public HtmlEncodeModelBinder(IModelBinder fallbackBinder) {
        if (fallbackBinder == null)
            throw new ArgumentNullException(nameof(fallbackBinder));

        _fallbackBinder = fallbackBinder;
    }

    public Task BindModelAsync(ModelBindingContext bindingContext) {
        if (bindingContext == null)
            throw new ArgumentNullException(nameof(bindingContext));

        var valueProviderResult = bindingContext.ValueProvider.GetValue(bindingContext.ModelName);

        if (valueProviderResult == ValueProviderResult.None) {
            return _fallbackBinder.BindModelAsync(bindingContext);
        }

        var valueAsString = valueProviderResult.FirstValue;

        if (string.IsNullOrEmpty(valueAsString)) {
            return _fallbackBinder.BindModelAsync(bindingContext);
        }
        var result = HtmlEncoder.Default.Encode(valueAsString);//wanted to add modal error instead of htmlencode if any script tags
        bindingContext.Result = ModelBindingResult.Success(result);

        return Task.CompletedTask;
    }

}

Help is much appreciated.

Thanks,