This is an interesting question that I don't think has been really well tackled in an unbiased way by English language works yet.

In general, a war economy (WWII style) was a planned economy by 1944-45. The military makes plans for the weapons it needs and then the government tries to get them produced, while also keeping the populace fed, the infrastructure operable, the army staffed and everyone happy enough to keep doing their part in the war effort. A planned economy takes a lot of organization to run, you need to know how much food you need and where you need it, how much raw materials each factory should get, how much of each kind of labor you need and how you're going to house and feed those workers. It's like a big crossword puzzle where every answer effects the decision next to it.

In contrast, western peacetime market economies rely on the market to do these complex allocations without a central government plan, or without a very detailed one at least.

In Germany, England, and the US, switching from a peacetime market economy to a planned wartime economy took years. The Germans started in 1936, the British in 1938 and the US in 1940, but none of these countries fully converted to a planned war economy until 1943, if ever. Creating the government machinery to administer a planned economy was difficult even when the political will was there, and it often wasn't in the initial years of the war or before it's outbreak.

The Soviets started from a lower industrial (and agricultural) base, but their economy had been "planned" for a decade. While the physical problems they had to contend with were great, they already had created the political and governmental machinery needed to quickly shift to a nearly fully planned war economy. Their Five Year Plans, while debatably successful in economic development, were like a dress rehearsal for a war economy in that they posed the same difficult allocation problems. I do think there could be more written in English on how exactly the Soviet transition was accomplished and how successful it was overall.

Now then, a few direct replies to points in your question. Steel production and coal production isn't a very accurate measure of overall industrial output. Germany was strong in these areas, relatively, but weak in others like production of rubber, oil, copper, and various trace minerals. While Russian Steel production was really hit badly by the 1941 invasion, their underlying resource base was still quite large. German Industry had to solve a lot of production problems due to shortages of stuff like copper, chromium and manganese.

As for the other point, in general Soviet armored vehicles were very efficiently designed for mass production, but they were still about the same size as German ones. The Germans produced more Panzer IVs than any other tank, and those are about the same weight as a T-34 (25-26 tons), plus the Soviets produced heavy tanks as well.

A few other factors made an important impact as well. The Soviets (like the Americans) did not have as much variety of AFVs as the German army and using the T-34 as the standard tank for the whole war minimized industrial delays due to retooling. Lend Lease aid from the US also helped the Soviet war effort, even if it was less than 10% of production, it was still able to help the Soviets avoid bottlenecks in their economy caused by the German invasion or problems in central planning, and to specialize, for example by bringing in American trucks so they could leave their tank factories churning out T-34s. Exactly how much this mattered to the Soviets is still rather unclear due to Cold War era bias.