As this Atlantic Council article argues NATO poses a threat to Russian imperialism not Russian security.

Source: https://www.libdemvoice.org/tom-arms-world-review-40-72956.html

Even before the war, experts pointed to a distinct set of ideas and beliefs coming from the Russian President, centred on rejecting the West and Russian imperialism, that were shaping Russia.

Source: https://www.euronews.com/2023/05/18/the-rise-and-fall-of-z-what-ever-happened-to-russias-talismanic-symbol

Others only thinly veil their extremism in traditional Orthodox Russian imperialism, exemplified by the Russian Orthodox Church (ROC) leadership and former paramilitary commander Igor Strelkov aka Girkin.

Source: https://www.euronews.com/2023/04/13/when-russia-calls-others-nazis-it-should-be-taking-a-hard-look-at-itself

The Circassian genocide - including the mass expulsion of indigenous people and the creation of a huge diaspora across the Middle East - was one of the darkest hours of Russian imperialism.

Source: https://www.heraldscotland.com/news/23566044.inside-russias-prison-nations-guide-nationalities/?ref=rss