To load formulas in a range I've used this method
ws1.Cells["B4:D4"].LoadFromText($"={con_Fu_LF},={con_Un_LF},={con_Fo_LF}");
and to evaluate I've called
ws1.Cells["B4:D4"].Calculate();
Opening the workbook I see strings in that range, for example in B4:
='Fu-LF'!F6841+'Fu-LF'!K6841
these are evaluated when I click on formula bar selecting a cell and press enter.
I want these to be evaluated automatically, how to do?