If there is the last member of the list, everything is just fine.
There is no last point between your nose and your monitor.
Let me pose a different problem, to demonstrate what I think is wrong with your argument.
You start with a reflective square slab that is half as thick as it is wide. You place another slab, which is half as thick as the first on top, then another half as thick as that. You continue doing this until your stack of slabs is as tall as it is wide. If you direct an ideal ray at this slab, along the symmetry axis of the stack, what does the ray do?
This situation is, once constructed, identical to the first ray described in your problem (the one that hits the face of the cube), but your argument would imply that the ray won’t reflect back, because whichever slab it would reflect from has another slab shadowing it.
There is no last point between your nose and your monitor.
Let me pose a different problem, to demonstrate what I think is wrong with your argument.
You start with a reflective square slab that is half as thick as it is wide. You place another slab, which is half as thick as the first on top, then another half as thick as that. You continue doing this until your stack of slabs is as tall as it is wide. If you direct an ideal ray at this slab, along the symmetry axis of the stack, what does the ray do?
This situation is, once constructed, identical to the first ray described in your problem (the one that hits the face of the cube), but your argument would imply that the ray won’t reflect back, because whichever slab it would reflect from has another slab shadowing it.
Look! Need not to be the last point. Zeno is resolved by infinite sums, which can give us finite numbers.
Yablo isn’t resolved and this is related to Yablo, not to Zeno paradox.