I think you can have two (or possibly more) interpretations for this. One being a dance or music; the other being to accomplish something with little to no effort. Are these two interpretations correct or is it just the former that's correct?
I couldn't find a source that explicitly stated the meaning to the name of the episode. I agree with your interpretations with both of them fitting moments in the episode. So let's break down the episode:
Venus is the setting for most of this episode so that fits just fine, the challenge is what the waltz stands for as. Stated on Merriam Webster the word Waltz can be a dance/music with a time signature of 3/4. This particular definition doesn't seem to have any real relevance to the episode, but if we take the whole timeframe in which Rocco Bonnaro is eluding Piccaro Calvino this could be considered a "dance".
The reason I say this because dance as a verb can mean to move quickly or nimbly. This is why sometimes in sports, for example American football, sometimes sports announcers will say a player "danced around the defense", meaning they eluded the defense. So I don't think it is that much a stretch to say Rocco was "dancing" away from Piccaro.
Another reference from the episode that can be used is when Spike and Faye take a commercial shuttle into Venus. They are doing this to catch some hijackers and defeat them very easily. This ties into the other definition of waltz being used as a verb and means to "to succeed at something easily".
Now this is in no way 100% the reason as to why the episode is titled this way but merely an interpretation as to why it could be.