My Site is acting weird

Hello, I don’t know what happened. But, I can’t add menus in my navigation menu bar. Whenever I add, it shows as pending.

My media library is not showing thumbnails of images and all images are shown broken. However, images are visible in pages & post.

I had created pages with elementor, but now all the page design is hampered. Currently, I have put my site on maintenance mode because it is looking damn ugly.

I also tried to upload my backup from updraft plugin which failed. I spent several hours but couldn’t able to find the fault.

The page I need help with: [log in to see the link]