Well given it's the reigning hegemon I'd say they are and need to be. That's the unfortunate fact. If the US wants other countries less interested in it maybe they could try not trying to dominate the world and do constant regime change, destabilization, sanctions, etc and let other countries develop in peace but they can't and there are apparent differences in who the main enemy is and how to approach that between the parties.

I doubt the Chinese or Russians are interfering but the Iranians are genuinely still furious at Trump for the killing of Soleimani and I actually do believe they'd probably like to kill him if it wouldn't cause a war and certainly to prevent his return as they think that Biden/Democrats who gave them the nuclear agreement are more reasonable and that they could still reintegrate with the west.

BUT I doubt their "interference" admits to anything. It's nothing, a couple of small, easily detected bot operations, maybe a hack of the campaign, a drop in the pond compared to the average US NGO "civil society fostering" in a given former soviet state and their level of societal interference even in hardened countries like China that take serious steps to curtail it.