If Charles VI had no surviving son, his heir would have been his nephews : the 3 sons of his brother Louis duke of Orleans, who came before the Anjou line.
My mistake. On checking the family tree I was looking at, it didn't have Charles V's children listed in birth order.
What is also important to understand is that if ever the king of England regains control of all the former possessions held by his Plantagenet ancestors in France, both France and England would be radically affected. The population of the french holdings of the Plantagenet was more important - rawly double - than the population of its english holdings. And France's population was 4 to 5 times as important as England's.
What you may have difficulties to accept is the fact that :
- the defeat of the Plantagenet/Lancaster dynasty in France was the condition for England's emergence as a top power ;
- and that the victory of the Plantagenet/Lancaster dynasty would have meant defeat of England because the key interests of the dynasty would have been on the continent. Most of England's ressources would have been dedicated to defending those stretched continental holdings.
Undoubtedly, which is why I went for an option where English sovereignty in France ended up being purely nominal, outside one duchy, sidestepping those problems.
The key steps needed are
1/ the failure of the Valois male line, passing their claim outside France, preferably to someone with an existing power base.
2/ a temporary victory for England, like Henry V won
3/ a lengthy period when none of the foreign claimants are strong enough to attempt to control France, and their are no plausible French claimants, allowing the French dukes to become effectively independent.
Step one, transferring the Valois claim outside France, means their claimant won't be seen as French, and will be opposed by their existing rivals, making it easier for England to win
Step three means England loses control of most of France, preventing the effective defeat you outline. If nobody is in a position to exert central authority in France, it's possible it could go the way of the HRE - not inevitable, but ending French political unity gives England effective victory.
Step two give England a nominal victory to match its effective victory. However, its actual rule would be restricted to a small appendage, leaving England as the dominant part of the state.
This requires France to have a run of bad luck, not just one point of divergence, but doesn't seem absurdly improbable. For instance, it's not that unlikely that the Duke of Orleans could die without sons, the same as his brother - though there may well be better points to terminate the main Valois line.
Certainly, the resulting history would look pretty contrived, but that just shows how improbable a lasting English victory was, and it's not as if real history is completely free of runs of bad luck.