I think you may try to create your desired range of cells in the column and set the common value to all the cells in one go, see the sample code for your reference:
Well, if you want to fill fixed/ common value into cells (in the column/row), my approach is better way for performance considerations. The Shared Formula approach is good but you would always need to calculate those formulas first to get the value at runtime or force MS Excel to recalculate the formulas when opening your output file into it which will surely take a little extra time.