I have a Brother J470DW printer. In the past I have been able to print double-sided. When I tried to do so with LibreOffice 5.0 Writer using Windows 10, I did not have that option. I checked the user community for a similar problem and found one where the user had an HP printer. I could not use the solution that user found although I did follow the same sequence “File > Printer Settings > select your printer > properties”. For the properties of my printer, there was no option for 2-sided printing, which is available using my printer’s properties when I print from email as an example. LibreOffice does not offer that option.
Double sided printing, whether automatic or manual, is a function of the printer driver being used, not a function of LO.
However, you can use the Print left pages / Print right pages to do the same - search Help with printing or go Tools > Options > LO Writer > Print …
If this helps then please tick the answer and/or show you like it with an uptick.