That is your prerogative to doubt, but as for my understanding, not only has Putin himself said explicitly that there is no Ukrainian identity, but that motive best explains Russian military actions. Other possible motives, e.g. countering NATO or protecting civilians in separatist regions, don’t hold up under critical analysis. (Assuming that Putin is a rational actor.)
That is your prerogative to doubt, but as for my understanding, not only has Putin himself said explicitly that there is no Ukrainian identity, but that motive best explains Russian military actions. Other possible motives, e.g. countering NATO or protecting civilians in separatist regions, don’t hold up under critical analysis. (Assuming that Putin is a rational actor.)
If you want an explanation for Russia's military actions that makes sense, read the article from the Marine Corps Gazette in this comment. Unfortunately I can't find a PDF link.