No, it isn't. Ruthenians, Belarusians, Ukrainians, and Russians are all descendants of the Rus. Belarus does not mean "White Russia", it means "White Rus."
> Originally, the name Rus' (Cyrillic: Русь) referred to the people,[1] regions, and medieval states (9th to 12th centuries) of the Kievan Rus'. In Western culture, it was better known as Ruthenia from the 11th century onwards,[2] Its territories are today distributed among Belarus, Northern Ukraine, Eastern Poland, and the European section of Russia. The term Россия (Rossija), comes from the Byzantine Greek designation of the Rus', Ρωσσία Rossía—spelled Ρωσία (Rosía pronounced [roˈsia]) in Modern Greek.
> Originally, the name Rus' (Cyrillic: Русь) referred to the people,[1] regions, and medieval states (9th to 12th centuries) of the Kievan Rus'. In Western culture, it was better known as Ruthenia from the 11th century onwards,[2] Its territories are today distributed among Belarus, Northern Ukraine, Eastern Poland, and the European section of Russia. The term Россия (Rossija), comes from the Byzantine Greek designation of the Rus', Ρωσσία Rossía—spelled Ρωσία (Rosía pronounced [roˈsia]) in Modern Greek.
https://en.m.wikipedia.org/wiki/Names_of_Rus%27,_Russia_and_...
Using exonyms to determine the "real" name of a place is also a very odd choice.