The reason the 'Russian Mafia' sounds so powerful is because a truckload of different ethnic organized crime gangs are labeled under the colloquial term 'Russian Mafia'.
If you list all of the gangs, you'll get :

Ethnic Russian gangs such as the Solntsevskaya Bratva, Tambov Gang, Izmaylovskaya Bratva ( they majority of the members of these gangs are ethnic Russian or Russian Jewish)

In the USA most 'Russian Mafia' members are Ukrainian Jews, Russian Jews or Belarusian Jews.

The Caucasus gangs such as the Chechens, the Ingush and the Dagestanis ( they are active in Russia but they've also spread throughout Europe )

Armenian criminal gangs

Azerbaijani criminal gangs

Georgian Mafia which in itself can be divided into ethnic Georgian, Georgian Jewish, Ossetian, Yazidi or Abkhaz criminal gangs

Baltic gangs, mostly the Lithuanian and Estonian criminal gangs

'Aussiedler' ( a term used to describe ethnic Germans who lived in Russia for centuries but recently migrated back to Germany ) criminal gangs who are very active in Germany

Central Asian criminal gangs ( mostly of Uzbek, Uyghur, Kyrgyz, Tajik and Turkmen origins) who are associated with the Islamic Movement of Uzbekistan, which is really more of an organized crime syndicate than a terrorist outfit

All of these gangs are incorrectly named under the collective term 'Russian Mafia'