I can't recall ever trying to type on 'pure psychedelics' although I can remember how extremely difficult typing was while fucked on MXE.
But that would make sense with it dissociating the body from the mind, and severely disrupting the wiring from brain to fingers (and all other parts of the body.)
Super high is the goal. You want to break through that barrier. You want to melt.
If you think you're too high with LSD, you haven't had enough.
Everyone has a breaking point in terms of dosage. Same thing with 5-meo-DMT. Some people resist, but you can only resist so much. If the dose is increased sufficiently, you will eventually crack everyone.