The thread already highlights this, but the target of the change dictates the label.
You are assuming capitalism is the steady baseline and communism is the disruption. But in reality, global capital is the true revolutionary force. It constantly tears apart the planet, destroying ecosystems just to keep expanding. It is insanely radical.
So if capital is the radical disruption, then what does it mean to be a conservative? 'oppose change' certainly doesn't cover it or much of anything at all. It means you want to conserve the basic conditions of life against this chaos. I am a communist because it takes a radical break to stop capital, but I am a conservative because the whole point is to defend the physical world from its destructive progress. Communist means, conservative ends.
I feel like your true definition of 'change' means 'movement toward liberation' if you could only be more specific. If a train is heading towards a cliff, hitting the brakes is conservative in the literal sense, but it is also the only sane and radical thing to do. You need a revolutionary tool (communism) to apply the brakes, but the goal is ultimately conservative (keeping the train from crashing).