russia doesnt have oligarchs for 15 years at least, it has the opposite of it. Oligarchs control the big chunks of economy, media and have a lot of political influence direct and indirect. What they have right now is some friends of the dictator who own something until dictator allows them.
The closest US has to olugarcha is Bezos and Musk, but they dont have each their own party and a few poket ministers in addition to owm bank and 20ish percent gdp.
US is still too big and rich for this shit