Grand Duke of the West

In September 1473, Holy Roman Emperor Frederick III agreed to crown Charles the Bold, the Duke of Burgundy and Grand Duke of the West, as King at Trier. This would have cemented the Burgundian holdings and would put Charles on equal footing with the Holy Roman Emperor and the King of France, and prior to that he had been vassals of both of them. Frederick III would flee Trier that month to avoid crowning the Duke. Charles would be killed in the Burgundian Wars two years later and his ambitious state was divided among the great powers of Europe. But what if, perhaps due to an increased Burgundian military presence in Trier, Frederick III stays and crowns Charles the Bold as King Charles I of Burgundy, Grand Duke of the West. With this new title and nominal support from the emperor, Charles is able to sway the bishops of Trier and other areas of his new Kingdom to sware loyalty to him. When war comes with the Swiss Confederacy, France comes to their aid, hoping to subjugate Burgundy to the French crown. Charles defeats the French with the help of the English and secures his independence from the King of France. He still fights Switzerland and the Holy Roman Empire. Charles takes the city of Cologne at the siege of neuss and subsequently sacks the city of Aachen. Frederick III is killed by his brother who crowns himself Albert VI.

How Burgundy Shifts European Geopolitics
The area that Charles's new kingdom covers has been a hotspot of European conflict since the Roman expansion into the area. After the Barbarian invasions and the death of the last Frankish Emperor, the territory briefly became the kingdom of Lothairingia before it was broken up and disputed between the French and the Germans. With the foundation of Burgundy, French and German emnity will be far reduced and the two will often find each other as allied against Burgundy. Burgundy's conflict with France will revive the alliance with the English that existed during the hundred years war. Burgundy's independence and the death of Frederick III would lead to a series of Habsburg dynastic disputes that would result in a more unstable atmosphere in the HRE, in turn affecting the reformation and Hussite Wars.

Burgundy will also naturally expand into the rich territories on the left bank of the rhine, this will definitely make it an enemy of Germany.

While Burgundy will probably be able to develop its own national identity and solidified language (likely sounding something like Luxembourgish, Dutch, or Alsatian) it still might have to deal with possible separatism, especially since the dutch reformation will likely still happen. Burgundy will be subject to its own wars of religion and will end up becoming protestant due to its political position though it will have to contend with the catholic Flamands and Rhinelanders who may still stir up trouble. Burgundy becomes heavily involved in both the Huguenot wars and the Thirty Years War. Burgundy takes up the role France took up OTL and the conclusion of the war ends in an expansion of Burgundian and Brandenburgian territories.

Burgundy will also take up a prominent role in colonizing the new world with prime maritime access through the netherlands and boasting a large population. Burgundy will set up successful colonies across the world and this will only serve as an extension of the conflicts with France. The Seven years war turns out similarly and France loses its colonial empire and falls to revolution. Napoleon takes power and invades Burgundy, occupying much of the country. Most of Burgundy is placed under French control, which leads to the outbreak of a guerrilla war against Napoleonic rule that would eventually lead to the toppling of the French Empire. The French occupation would solidify Burgundian national identity in opposition to the French Empire.

The development of socialism in the 19th century, a lot of which happened OTL in what would be Burgundy, would definitely affect the country.