So your point is that Russia does try to interfere in American and other foreign elections, they just aren't very good at it?

The electoral college makes it easier for foreign actors to influence American elections. Instead of convincing 3 million people to change their votes from Clinton to Trump in order to effectively influence the election, the entities spreading FUD only need to influence a few thousand in key swing states.

From your Brookings article:

The bottom line is that the Mueller report clearly shows that the Russian information operations were highly adaptive to the political context in the United States, followed a seemingly well-thought out strategic plan akin to a marketing or public relations campaign, involved direction from Russian intelligence, and were incredibly effective in infiltrating American media while influencing public debate around the 2016 election.

The article from the Nation is a poorly sourced opinion piece from someone who seems to have a very poor understanding of how the Russian intelligence works. The key "gotcha" in the article is that IRA is not a Russian government agency, rather a private company run by Russian individuals.

This isn't in contradiction to the Mueller report, it's common for Russian intelligence (and other intelligence agencies around the world, including CIA and other American intelligence agencies) to use private corporations to carry their agendas. As pointed out by the Brookings article Russian intelligence directed the actions of IRA, even though IRA and its employees weren't directly employed by the Russian Government on paper.