First off, you're right about the timing of Gustavus, that's my mistake.
Second, several things about Wallenstein and the Swedes: (1) Wallenstein wasn't entirely dependent on plunder because he also had Friedland, which Wedgwood describes as being a territory totally devoted to supporting his military machine and which played a huge role in supplying and financing Wallenstein's army; (2) Gustavus understood he was an outsider and engineered the perception of himself as a liberator to overcome the idea that he was a dangerous foreign conqueror.
Now, even though as it is the Swedes in actual history did much damage to central Europe in the Thirty Years War, if Gustavus has to support himself by living off the land very quickly the entire German nation lines up against him. Even John George of Saxony preferred the Emperor to Gustavus initially, because at least the Emperor was (for the most part) a German whereas Gustavus was an outsider. So I think Gustavus really needed France or some other source of revenue. Because living off plunder is pure box office poison for someone who plans on being the President of the "Corpus Evangelicorum", and who is selling himself as someone who wants nothing for himself but only what is best for the German Protestants.
Second, several things about Wallenstein and the Swedes: (1) Wallenstein wasn't entirely dependent on plunder because he also had Friedland, which Wedgwood describes as being a territory totally devoted to supporting his military machine and which played a huge role in supplying and financing Wallenstein's army; (2) Gustavus understood he was an outsider and engineered the perception of himself as a liberator to overcome the idea that he was a dangerous foreign conqueror.
Now, even though as it is the Swedes in actual history did much damage to central Europe in the Thirty Years War, if Gustavus has to support himself by living off the land very quickly the entire German nation lines up against him. Even John George of Saxony preferred the Emperor to Gustavus initially, because at least the Emperor was (for the most part) a German whereas Gustavus was an outsider. So I think Gustavus really needed France or some other source of revenue. Because living off plunder is pure box office poison for someone who plans on being the President of the "Corpus Evangelicorum", and who is selling himself as someone who wants nothing for himself but only what is best for the German Protestants.
But he'd already arrived!
You then need Richelieu to cut funding Gustavus, but of course he already have his stepping stone into the HREGN. Cutting funds would be important, but then Gustavus would soon adopt Wallensteins method of plundering the land to sustain his army.