[oneshtein]

Yes, actual Russians (русичи) are from Russia tower, now Old Russa tower (Старая Русса), which was on Russia river, now Porussia river, but Russians renamed their country to Ukraine, to avoid confusion with Russian (Moscow) Empire.

Russian (Rossian) Federation doesn't contain a region named "Russia". Russians (Russish, русские) are believers of Russian Orthodox church and not a nation at all, like Catholics are not a nation. Rossians (россияне) is.

Many nations, such as Tatars, Mordva, etc., were turned into Russians (Russish) by a process called "Russification", when stolen Russians Orthodox Church was used as tool to enslave peoples and erase their identity by giving them Russian names and forbidding to use their native language in favor of Russian Church Slavonic language. Scratch a Russian and you find a Tatar[1].

[1]: https://www.oxfordreference.com/display/10.1093/acref/978019...