I like the ideas you mentioned however one of them already exist but not in the RPG-sense like Kingdom Come Deliverance does. I LOVE Bladestorm The Hundred Years War, even bought the new version on PS4. It’s not RPG and it has fantasy elements but is still a highly enjoyable game that unfortunately not many people bought.
Another suggestion since no game was ever made surrounding this battle or this period:
Kingdom Of France VS County of Flanders, most famous battle is the Battle of The Golden Spurs were mostly Flemish peasants (Flemish myself) won against French knights and infantry in 1302 at Kortrijk (Courtrai). Almost no French were spared since they commited torture, rape and murder in cities before the battle. Really famous here, even got a film long ago.
On July 11, 1302, the townsmen of Courtrai and other Flemish rebels defeated a French army outside the walls of their city, in what is considered one of the most important battles in the Middle Ages. The victory of infantryman over a mounted forces of knights was a shock to the current military thought of that period.
The rest of the French army quickly fell apart, and the total victory was secured. It was a terrible loss for French nobility as over 70 lords were killed. The Flemish collected 500 golden spurs from the dead indicating a large amount of wealthy elite they dispatched. These spurs were sent to be displayed at a local church.