A (nontrivial) 4D STM is all they need. AIUI no new synthesis. But.. that's "just" rendering software "just" like
https://en.wikipedia.org/wiki/4D_scanning_transmission_elect...
(Not in the sense that "time" is involved but in the sense that what distinguishes 3D from 4D is almost only software . The same way you can see 4D "all at once" on your 2D screen,but 4tuples coords!= code)
But then again IBM have claimed quantum software=quantum hardware (see above).. they might or might not understand what is or is not needed?