In my setting there is a race descended from Gigantopithecus blacki. These creatures retain much of their ancestors physical features, such as:
•An impressive height of 2.75 meters (9 feet in freedom units)
•Disproportionately long arms and plenty of strength to use them (as strong as five men)
•They retain an herbivorous diet that necessitates a lot of eating and a generally reserved energy expenditure until combat starts, at which point they are much more strong and agile than humans
•They have a gular sack like a siamang that lets them be extremely loud.
•Their wrists can rotate much further than a human, which could make for very interesting sword fighting tricks.
The giant tribes have all sworn fealty to human polities in some form or another due to the fact that humans outnumber them hideously and the giants are intelligent enough to understand that they need the assistance of humans to survive. Humans in this setting are at a 14th century European level.
While on its face giant warriors would be good, they have a few serious disadvantages compared to humans.
•As mentioned previously they need to eat a lot of food.
•They absolutely suck at endurance running compared to humans and won’t be able to march as long.
•They are a bigger target for archers and arbaqusiers.
What also needs to be taken into account is their cognition. They are equivalent to humans in their reasoning skills, but they are significantly less ambitious or creative. They learn how to use spears, bows, swords, and even guns with ease as long as they can actually wield them.
So taking into account these giants strengths and weaknesses, what would be the best application for them in a medieval military?