EnumBinding.cs

namespace _;
public class EnumBinding<T> where T : struct, Enum
{
    private const bool IgnoreCase = true;
    private const bool IgnoreInt = true;
    
    private T value;

    public static bool TryParse(string value, out EnumBinding<T> result)
    {
        return TryParse(value, null!, out result);
    }

    public static bool TryParse(string value, IFormatProvider provider, out EnumBinding<T> result)
    {
        result = new EnumBinding<T>();
        if (IgnoreInt && int.TryParse(value, out _))
        {
            return false;
        }
        
        var success = Enum.TryParse(value, IgnoreCase, out T parsedValue);
        if (!success || !Enum.IsDefined(typeof(T), parsedValue))
        {
            return false;
        }
        
        result.value = parsedValue;
        return true;
    }

    public static implicit operator T(EnumBinding<T> e) => e.value;

    public override string ToString() => value.ToString();
}

Example usage:

app.MapGet("/", ([FromQuery] EnumBinding<MyEnum> param) => 
{
   MyEnum enumValue = param;
});