Note that I also tested libreoffice 6.0.6 that's installed by default in Ubuntu 18.04 (the deb packages, not the snap), and it took over 20 minutes to load the same document, so it's not a snap-specific problem.
Note that I also tested libreoffice 6.0.6 that's installed by default in Ubuntu 18.04 (the deb packages, not the snap), and it took over 20 minutes to load the same document, so it's not a snap-specific problem.