Once it becomes clear that Austria will be taking French lands, the Dutch are going to stop supporting them. Once the Austrians are done reconquering lands lost to the French, surely, from the Dutch POV, Austria will try to retake the rest of the Netherlands.
As for the English/UK, how do you sell this to Parliament? British troops are treasure wasted to enrich Austria?
Except in 1709, the Alliance as a whole, including England, the Netherlands, and Austria, was willing to give the entire Spanish inheritance, including Southern Netherlands, to Archduke Charles. And it even demanded that all the territories taken since 1648 be given back by France, which included Franche Comte and Artois to the Habsburgs.
Louis XIV agreed.
Then they demanded he use French troops to eject his own grandson...
Anyway, it's moot, since nobody expected Joseph I to die without a son and leave the Empire to Charles.
So assuming that they don't demand Louis XIV to eject his own grandson, the war would end in 1709 or 1710, and the Spanish inheritance goes to Charles.
Everything is peachy for the alliance. France is humbled and reduced to it's 1648 borders.
Then suddenly, Joseph I dies without sons in 1711, and Charles becomes Holy Roman Emperor and Archduke of Austria, King of Austria, etc...
Would there be war?
I don't think so. All the combatants would be exhausted from almost 20 years of continuous warfare from 1689. They'll grumble, but after having fought so hard for "Carlos III" to be king of Spain, they would be too tired to fight him being Charles VI, Emperor.
So we have the recreation of the Empire of Charles V!