Yes it is, and Russia is increasingly being recognized by scholars as such.

This is especially visible in the war against Ukraine, which is colonial in nature. Russia has invaded another country on imperialistic justifications ("reunification of Russian lands" etc), is using domestic minorities as cannon fodder to alter the ethnic composition of Russia in favor of Russians, is committing genocide against Ukrainians to destroy them as an ethnicity, and is resettling ethnic Russians into occupied territories to permanently alter Ukraine's ethnic composition.

The whole "NATO expansion" narrative is complete bullshit when the initiative to join NATO has come from Russia's neighbors, who want to gain the protection of its mutual defense clause in the hope that this would deter Russia from invading them.

Russia has been the aggressor in this part of the world for centuries, and the rest is a reaction to that. Russia is the sole reason why Northern and Eastern Europe have militaries at all; if it weren't for Russia, they could be disbanded overnight.