Printing presentation handouts

I want to print out presentation handouts with 2 slides per page (Print → Document handouts → slide per page 2). The Libreoffice puts two slides on top of each other but in Landscape orientation, which looks very odd with empty space to the right and with the bottom slide cut. Option to change page orientation to portrait (which is natural in this case) is blocked and in seems no way to go arownd this problem. This option (Printer setting → Paper → orientation) worked perfectly in version 4, but in version 5 it remains blocked by unexplainable reasons throw many updates.

To change the orientation to Landscape, go into View → Handout Master. Then right click on the page → Format Slide… Here you can change the orientation of the page to Landscape.

I have not found a way to print my handouts in Portrait, which is what I actually want, except to first print them to pdf and then use a pdf viewer to do the actual printing.