All the actions accessible from the 3D editor view are undoable including object selection, actions at the sidebar (adding modifiers, changing their attributes) with the exception of switching the print, filament, SLA material profiles.
You can undo or redo multiple steps at once by right-clicking on the Undo or Redo button and selecting a point in history. As each of the snapshots has an expressive name assigned, it is easy to orient even in a long list of actions.
