because of the cultural barrier is hard to measure how big is opposition to Putin regime on there, it makes me genuinely wonder if they just absolutely hate Putin's guts or if he's actually seen as a genuine good leader
There are two main kinds of Putin opponents in Russia:
The Liberals:
The professional losers of Russian history, when the Liberal is not idolizing Western Europe or raging about the very real issues plaguing Russia, they dream of an alternate history where the Mensheviks won the Russian civil war. While the Liberal has many accurate and fair criticisms of Russia (corruption and social inequality being the big ones) their foreign policy is so weak and cucked that they would probably ruin everything. Economically they are very capitalist and reform-minded compared to other parties.
The two times Liberal Republicans did get into power in Russia (February 1917 and 1990) they promptly drove the country into a fucking ditch and nearly destroyed it. Has support among the urban middle class and some reformist-minded oligarchs
The Ultra-nationalists:
A "strange bedfellows" alliance of Tsarist Nostalgics and Russian Socialists, the Ultranationlists in Russia are not in fact an invention of Call of Duty 4. They tend to be to the left economically, believing Putin's rule to be far too pro-oligarch and too free-market in approach. They also believe Russia's foreign policy is not aggressive enough, and dream of a reunited Rus as well as kicking out the Muslim migrants from Central Asia.
That being said, they still support Putin as a better option than the Liberals who they hate, and are allied with the United Russia party of Putin. These Ultra-nationalists played a very important role in the establishment of the breakaway Donbas Republics. One prominent example of this is Strelkov Girkin, who was the first defense minister of the DNR. Alexander Dugin is one of the more prominent faces of the ideology.
Has support in the Russian army, security services and parts of the Diplomatic corps. Support base is some older Russians, Army veterans and military officers.