Helpo de LibreOffice 7.5
In LibreOffice Calc, there is a way to "rotate" a spreadsheet so that rows become columns and columns become rows.
Select the cell range that you want to transpose.
Elektu menueron Dosiero - Eksporti.
Click the cell that is to be the top left cell in the result.
Elektu menuerojn Redakti - Alglui Speciale.
In the dialog, mark Paste all and Transpose.
If you now click OK the columns and rows are transposed.