i wrote up something like this for my ASB ATL after asking a similar question here a long time ago. basically, with a POD of Horatio Gates being killed on the first day of Saratoga, Arnold experiences greater earlier successes but is still passed over for promotion until 1780 when Washington insists that his deeds be recognized after Charles Lee is dismissed. Arnold doesn't feel snubbed by the Continental Congress and therefore stays on the Revolutionaries' side through to the end of the war. after the war ends, he's reassigned to the Ohio Territory to fight the local Amerindians (just an unfortunate reality of the era) until 1789. after that, he retires and becomes the first superintendent of West Point and eventually campaigns for the presidency in 1800 as a Federalist against Jefferson. he narrowly loses the election and passes away the following year as IOTL.