Personally, I would avoid using the term oligarchy because it has become something of a trend term used as a negative label in US political culture and synonymous with Russian (self described) backwardness and corruption.
I would write in a nod to how humans usually dilute themselves in their political labels and oversimplified ideology. No one calls themselves what they are directly. Like I default assume every monarch believes in their own fantasy meritocracy.
The concept you described could hold parallels to the papal conclave and election process. I would use this as a loose framework to make the ideas relatable.