the "both sides" ceased to exists once Putin started the aggression against the whole country, and specifically its population. While it is true that there had existed a Donbass issue, it doesn't matter right now as under excuse of that issue, Putin started an ethnic cleansing and genocide against Ukrainians. There is no other side in genocide. Putin is extremely clear laying his approach and goals specifically in his 2 last Ukraine speeches.

The possible NATO expansion/Ukraine joining is also just an excuse (solving it is a kind of "nice-to-have" side effect) and the West attention's misdirection. Putin's direct goal in the current action and a major corner stone of his overall policy is non-existence of Ukraine and Ukrainians (in the idiosyncrasy of the "Russian world" philosophy the Ukrainians are the traitors who chose West side and thus have to be punished a-la "Taras Bulba" style). According to him only Ukrainians who are ready to deny their ethnicity and recognize themselves as Russians are allowed to exist. It is a great tragedy that many Russians do partially or fully subscribe to that view without fully recognizing the catastrophic reality it leads too.

Putin's policy is clear fascism. It isn't well recognized on the West as West plays coy when it comes to fascism and isn't yet direct target of Putin. In Ukraine and other directly targeted countries the term "russism" ['rashizm'] for "russian fascism" has been a normal everyday word as they have been feeling its threat for years.