Convert Excel Formula to Sharepoint Calculated formula

I’m having difficulty converting this Excel Formula to Sharepoint calculated formula. Hoping someone can help.

=IF(OR($F13>=TODAY(),ISBLANK($F13)),0,IF(ISBLANK($G13),NETWORKDAYS($F13,TODAY(),Reference!$E$2:$E$31),NETWORKDAYS($F13,$G13,Reference!$E$2:$E$31)))

F13 = Requisition Open Date
G13 = Requisition Closed Date
Reference!$E$2:$E$31 = Holiday Dates

I’ve created this in SharePoint for DAYS OPEN which works but doesn’t take into account if Requisition Open Date is Blank. It will still calculate the column and show a number like 31,636:

=IF(ISBLANK((Candidate Start Date)),DATEDIF((Requisition Open Date),TodayDate,”D”)-IF(WEEKDAY(TodayDate)=7,FLOOR((DATEDIF((Requisition Open Date),TodayDate,”D”)+WEEKDAY((Requisition Open Date)))/7,1)*2,FLOOR((DATEDIF((Requisition Open Date),TodayDate,”D”)+WEEKDAY((Requisition Open Date)))/7,1)*2)+IF(WEEKDAY((Requisition Open Date))=7,2,1),(Candidate Start Date)-(Requisition Open Date)+1)

Thanks