I can see a folder was added with shrotcuts just like the Libreoffice 5.4 folder that DOES show up in the all programs list, but the new folder, Libreoffice 6.0 created during install, which is right next to the old Libreoffice 5.4 shortcut menu does NOT show up on in the All Programs menu on Win10. What’s up with that?
Have you installed both versions?