Check your numbers. Number of tanks as of June 1941. And Germany oil consumption and sources as of 1940. You'll be surprised.
You're also changing the goalposts. We're talking about 1939, not 1941, which was after two years of herculean production.
https://defense.info/re-thinking-strategy/2018/10/oil-and-wa...
By 1939 Germany was at less than half of its peak, and only 24% (replaceable, 1936 composition) came from Romania+USSR.