I can view CC libraries, create new libraries, create groups. I cannot drag anything into a library. The Add Elements icon (plus sign) is grayed out.
macOS Ventura 13.4.1 (c), M1 Max
No problems for me with InDesign 18.5 and Ventura 13.5 on a MacBook Pro similar to yours.
Try updating to Ventura 13.5.
If that doesn't work, restore your InDesign preferences and caches. Here's how: