Assuming your table name is TBL_Holidays and saturday, sunday are non-working days
You can try this to get the working date:
DECLARE @NoOfWorkingDays INT;
SET @NoOfWorkingDays = 5;
DECLARE @StartDate DATE
SET @StartDate = '20201001'
DECLARE @CurrDate datetime;
DECLARE @Counter INT;
DECLARE @DayAdd INT;
SET @Counter=0;
SET @DayAdd =1;
WHILE (@Counter < @NoOfWorkingDays)
BEGIN
SET @CurrDate = DATEADD(DAY,@DayAdd,@StartDate);
If DATENAME(dw, @CurrDate) NOT IN ('Saturday', 'Sunday')
AND (@CurrDate NOT IN (SELECT Date_FMT FROM TBL_Holidays))
SET @Counter = @Counter + 1;
SET @DayAdd = @DayAdd + 1;
END
SELECT @CurrDate;