Tbf, damn near all ancient monarchs of note could be justifiably described as psychopaths. Cleopatra usurped and bumped off two of her teenage brothers (the first one was trying to usurp her before she could do the same to him, the second by all accounts did nothing wrong).

Of her contemporaries, her lover Caesar bragged about genociding a million Gauls and enslaving another million. And Augustus, who brought her down, proscribed over 2000 Roman citizens (including over 100 Senators) in a sanguinary purge & killed thousands more in civil warfare alongside Mark Antony, Cleopatra's other lover, before their alliance broke down and they went to war. As we know, Augustus won and managed to transform his image from that of a blood-soaked dictator into a genteel and genius elder statesman. The other Hellenistic monarchs weren't any better and some were quite a bit worse than Cleopatra.

So yeah, she was probably a power-tripping psycho with a good deal of blood on her hands, but that just puts her in the good company of her neighbors. The same is true of the others. (For example, before we feel too bad for the people Augustus purged, we must remember they were Optimates - basically the Ancient Roman equivalent to our shitty establishment today. And so on, so forth.)