President Putin wasn’t shamelessly admitting to blatant imperialism in the 21st century but making a valid point about the circumstances in which external forces compelled him and his predecessor Peter the Great to militarily act in defense of their co-ethnics and their country’s objective national security interests, both of whom were justified in their ongoing special operation in Ukraine and the Great Northern War with the Swedish Empire respectively.
Here is Zakharova fielding the question.
https://www.youtube.com/watch?v=IHRaT_Et5Og