In writer I add keyboard shortcuts to notebookbar.ui and notebookbar_compact.ui file, so it will be possible to switch with an keyboard shortcut to an different tab.
Can someone implement the code to use the functionality from the .ui file.
Maybe the Design Team with more UI knowledge will be able to confirm this.
Shortcuts are not defined or implemented in the ui file (wouldn't be a UX task anyway). And actually the tabbed variant of the Notebookbar works as expected: activate the toolbar/notebookbar with F6 and use the default key to toggle through tabs, which is ctrl+tab.
Note: the keyword needsUXEval requires to add ux-advice@ to CC