Multiple button wigets, with linked uno commands (mostly to set object mode), are assembled into toolbars--e.g. Basic Shapes now on the Standard toolbar. The toolbars can be activated/opened with keyboard movement--but then the individual buttons (mostly modal selections) can not be navigated and selected with keyboard cursor or tab movements. A UI and a11y issue, as actions performed with mouse movement and selection should mostly be supported with keyboard actions as well. Toolbar navigation is pretty fundamental UX.
Draw has some additional toolbar groupings
Sorry for the noise, if you enter into the toolbar correctly with an <F10> and multiple <F6> progressions to reach the correct toolbar, and then cursor/tab onto the split button for the grouped toolbar. On open of the grouped toolbar--cursor (R,L) does traverse the buttons. <TAB> and cursor (U,D) do not.
Not ideal, but it does work. I think the missing cursor Down tripped me up. Sorry for the noise.