They were at it at least a year before the 2016 election cycle. I believe it was the CIA that said Russia was the one that created the Jade Helm scare in 2015 through social media influence.

Jade Helm was the name of a training operation of the US military in central TX near Temple. The Russians created a bunch of posts claiming that Obama was taking over local Walmarts and emptying them of all merchandise to use as prisoners for his political opponents. They even drew diagrams of the insides of the stores with the holding cells and everything. So great was the Russian influence that Abbott (who is still Governor of TX) ordered the TX National Guard to watch the training exercise and make sure that the US military wasn't storming homes and taking prisoners.

there have been literal articles and reports by the FBI that Russian interference

There have been literal articles and reports by the FBI of domestic white nationalist organizing and domestic financing. Significantly more money and manpower is documented as entirely domestically organized, although a sizeable amount is moving between NATO and other Five Eyes states. We're talking on the scale of tens of billions moving between domestic financiers - like the Mercers, Thiel, the Kochs, etc - and domestic fascist media/organizing. That dwarfs Russian state interventions. Its orders of magnitude different.

That’s why it’s been attributed to the Russian government.

Why do you search for the speck in your neighbor's eye when you have a plank within your own?