Lightroom classic now randomly only shows pictures, disabling access to all tools.

It is difficult to understand without a picture of the screen, but I will guess that maybe the Secondary Display window is covering the main window, which is a common problem. The symptoms are not seeing the side panels, and the top bar saying Normal/Live/Locked instead of the module picker.

If this is what’s happening, you’d be able to resolve it by looking at the command Window > Secondary Display > Show, and make sure Show is deselected.

I can't tell what you mean. Could you please show us a screen capture? Please use the "Insert Photos" icon to include your screen capture in your reply. Do not attach files.