I’m aware that the principate was a republic in name only, but the senate did have some power and decision making abilities. They conspired against Domitian and did pick some emperors.

Diocletians tetrarchy was...interesting to say the least.

Sadly even though he made it a de facto hereditary succession it still didn’t fix the issue of succession. Maybe if Crispus had succeeded him he could’ve fixed it but sadly we’ll never know.