In Sweden, many people on the left wing are against helping Ukraine. "American imperialism" is, according to those type of leftists, something one should always oppose regardless of what or why America supports something. That said, most leftists (and right wingers) here are pro Ukraine. Strongly. In fact, during our election it wasn't even an issue. No relevant party opposes it.
If I wanted to destabilize the West I'd fund both fringes, not just one. putin doesn't care about ideologies. putin only cares about destabilizing the West regardless of what we actually end up with. The fact is that many people on all kinds of ideologies for many different reasons are pro russia. It's not a right or left wing thing really. Making it a partisan thing to help Ukraine doesn't help Ukraine.