that's true roman dynasties almost always were: the first one is a great ruler and then his successors are progressively less competent until one finally gets himself killed along his family or childless and then the generals start to fight until one becomes emperor and then the cycle repeats again or we have the third century crisisJulia the Elder could born as male so now Augustus then would has son. Augustus then could groom him as his successor. With good luck this could produce bit longer stability altough probably Caesar Dynasty not last very long. Roman dynasties had generally pretty poor life expectacy. In few generations there probably will be emperor who ruins everything and yet manage to kill all of his relatives like Nero did in OTL.