There’s definitely a gradient in terms of economics. So you’re right, I wouldn’t place him squarely in the middle of that quadrant, and I certainly wouldn’t call him a social democrat. But compared to the rest of the Republican field, he has gone far further in condemning globalization, criticizing free trade, supporting tariffs, calling for government spending on infrastructure, and even at times praising socialized medicine and saying that under his “fix” for Obamacare, there won’t be “people dying in the streets.”
Of course, Trump has been extraordinarily light on policy, and it would be hard to tell which of these things he is serious about and which he could flip on. Rhetorically though, I think the move towards working class-focused economics is there.