• You performed the test for "Mobile" connection and pointed to the homepage with a number of large images, because you have the Timeline/Outline as well Posts browsing enabled for mobile viewports on homage. Thins tanked your score.
• Cover image is relatively large - you can upload a smaller, better compressed image via Studio.

There will be a number of improvements in v14 final, and we expect Desktop score to be in 97-99% range with mobile score comfortably 80+.