I click 'Toggle Context Pane' many times a day when reading articles in Zotero. It would be great if there was a way to do that with a keyboard shortcut.

Alternatively/additionally 'Toggle Context Pane' could be added to the View menu (maybe below Use Dark Mode For Content?) since macOS lets users assign keyboard shortcuts to main menu items even if the app itself doesn't do that natively. Maybe you could also consider adding other frequently used app features to main menu for the same reason.