There are two levels of problems with a technocracy.

The first is a problem that’s common to all hierarchical systems, entirely regardless of their specific nature. They will, each and all, sooner or later come to be dominated by people who hold the positions they hold solely because they most lust for those positions and are most willing to do absolutely whatever it takes to gain and hold them.

It makes no difference what sort of limitations or stipulations might be in place - if there is a position that holds authority over others, it will eventually come to be held by the most vicious and conniving bastard in the organization, because they will be willing and able to go to lengths to which nobody else will go.

The second problem with a technocracy is ancillary to the first, and common to all hierarchical systems that focus on some specific philosophy or identity. The positions of power will still come to be held by the most determined psychopaths, but unlike in a more general system, the abusers in power will have an additional claim to legitimacy by paying lip service to the ideal. They’re generally able to act even more destructively than other psychopaths, since they can hide their malevolence behind the philosophy or identity both before and after the fact.

Or more simply - peoblem 1 is that you end up with psychopathic assholes, and problem 2 is that you end up with psychopathic assholes who have even more power than your run-of-the-mill psychopathic assholes because, after all, they’re experts.