However, unfortunately the icons in all the office programs are absolutely tiny and impossible to see properly on my 4K display.
I have a Dell XPS 15 9560 display which is a 4K display. Is there any way to increase the size of the icons, menus and fonts? It's possible in Libre Office but it doesn't seem possible in SoftMaker...

Here's examples of what I mean (menus, buttons etc. are way too small to use):

