Fascism comes in different forms and sizes. The Nazis are fascists but not all fascists are Nazis. One of the common misconception about fascism is thinking they value nationalism based on ethnicity alone, which is not the case. The original fascism of Mussolini tried to rally people under the greater Italian nationality. Mussolini did not care about ethnicities and did not care about persecuting the Jews as matter of fact. It was only later under Hitler's pressure that he did. After all, Mussolini was trying to recreate the Roman empire, a multicultural empire.

Similarly, Salazar's Estado Novo in Portugal would also be considered fascist but expected his subjects of other races and ethnicities to rally under the Portuguese identity. He was fervently anti-Nazi and disliked Hitler which is why Portugal benefited from the post-war NATO alliance and received tremendous Western economic aid.

One of the fascist value is rallying under common group heritage, whatever a fascist group deem it may be, but not necessarily under one ethnic identity. Putin basically demanded the same from Ukraine by writing a childish essay of his that Ukrainians and Russians are one people, denying the Ukrainian right to self-determination and distorting history. And there are multitudes of reports of Russians abducting Ukrainian children and sent to Russia. Not to mention the mass graves found a week after the initial invasion of Russia north of Kyiv. So, I don't know what you're talking about civilians weren't killed deliberately in huge numbers. Obviously you're consuming pro-Russian propaganda to claim "not many civilians died". Doesn't matter if there were Brownshirts or einsatzgruppen group alike that did those from the Russian side. The fact of the matter is that it happened in large scale.

There is a video explaining that Putinist Russia is basically a fascist state. Putin and many elites are inspired not by Alexander Dugin-- a fascist-- but by Ivan Ilyin, who is arguably a fascist adjacent, who himself was inspired by the idea from 19th century czarist Russia that the country is "eternally innocent". Many Russian intellectuals including Fyodor Dostoevsky and Leo Tolstoy subscribed to it. This laid the groundwork to Russian ultranationalism and exceptionalism to pursue their own sphere of influence.

As for the usual pro-Russian rhetoric of Azov and the likes, there are fascists and neo-Nazis in all countries. It doesn't justify attacking invading another country. The Azov and other Ukrainian neo-Nazis were insignificant until Putin meddled in 2014, stoking tensions. Before 2014, ordinary Ukrainians and Russians get along quite well.

Putin could have just let the "Russian peacekeepers" he stationed, just before the invasion, to act as deterrent in Donbas and Luhansk to support the separatists. He said the soldiers are not there to invade; but he lied and invaded anyway. Putin's invasion would be like if Turkey invaded from Turkish-controlled northern Cyrus to invade the rest of Cyprus "to protect" Turks in the southern part of the island. Or, the Irish government invading Northern Ireland and the rest of UK under the excuse of protecting Irish Catholics (as a matter of fact, the Irish government did have a plan to invade Northern Ireland using the excuse to protect Irish Catholics in the North but did not act on it because, unlike Putin, it is a terrible idea).

Putin did not bring enough troops into the war, because the planning was made under the FSB and not the military who should know better (but then again, the Russian military hasn't done well even up to this point so even if they drew the invasion plan themselves, it may not have been any better). Russian soldiers did not even know they were going to invade. It was only Putin and his inner circle of yes-men who knew of the plan and thought it is a good idea to invade a country that historically dislike them. Deluding themselves that Ukrainians will welcome them with open arms which is why they planned things shoddily. That's how much Putin's circle think low of the Ukrainians; and that could not get anymore fascistic.