There're definitely people in Russia who are against the "special military operation" - c.f. protests after Putin ordered a partial mobilization.
Have any of these people explained what their preferred end state* looks like? For example, most Ukrainians are against any end state that involves ceding Donetsk, Luhansk, and Crimea. Are there anti-war parties in Russia that agree with cancelling recognition for Donetsk/Luhansk and returning Crimea to Ukraine?
I'm especially curious if Alexi Navalny has said anything. I know he has said "stop the war", but I'm unaware if he's described how he prefers to resolve the status of Donestk/Luhansk/Crimea.
*Definition: "end state" is the state after any formal peace treaty is signed. If no peace treaty is ever signed (e.g. the situation between North Korea and South Korea), then presumably the end state would be uti possidetis.
Tangentially related: Is there a faction in the Ukrainian parliament favoring an immediate ceasefire? and Is there a political faction in Russia publicly advocating for an immediate ceasefire? which establish that these factions do exist, but do not explain what their preferred end state is.