Alexis was alive and kicking at age 21 so his ascension would be assured. Russia was never isolationist nor were there any hard core reactionary clique to seize power Alexis would have done what any new Tsar would do- change those policies that he disagreed with but keeping most intact Peter the Great was a leader who lacked patience and made many unneeded changes.Was his son Alexis still the heir in 1711? Would there have fbeen reversal in Russia and a return to the isolationism? A closing of the "Window to the west?"
I wonder if Sweden could have reconquered anything at this point, but if the king returns, and a new Swedish offensive is started, and it has some limited success, then there might have been forces in Russia questioning the continuation of a costly war, perhaps forcing the czar to give up something after a Swedish victory in the battle of Viborg in 1712. This concession would not be enough for Charles, who wants all provinces back, probably including Courland, and a support for Stanislaus as Polish king. Could Charles then take Petersburg, or would the front stabilise there, with the war ending only after his death?The country would rally to him and he would have no reason to give up the miliatry gains the country had made