You’re encountering an error in comparing the DayOfWeek enumeration with a string value. To check if the current day of the week is between Monday and Thursday, you should compare it with the corresponding DayOfWeek enumeration values, which are integers.
Could you please use the following expression once?
var CurrentDate = DateTime.Now
If (CurrentDate.DayOfWeek >= DayOfWeek.Monday AndAlso CurrentDate.DayOfWeek <= DayOfWeek.Thursday)