If you watch your video closely, you'll note that they are attempting to accurately represent the year 1415. That is important given that Bannerlord's world is already history by the time of Warband, and I believe 1415 would have been late even for Warband.
Where the shooter describes how he decided to go for a lesser weight bow, 160 instead of 200 pounds, that is a significant difference. He talks about how he started shooting in his mid to late teens, and he shoots two or three times a week, so he feels he is comparable to the archers in that battle -- even though those archers likely started well before he did, and we have records showing people were much more physical stronger in this age. In Scandinavian cultures there was a practice by which a man's strength would be determined where he would carry a massive stone around something like a sheep-pen. If he could carry roughly 360 pounds, he was full-strength, 180 pounds and he was half-strength and half the value. I can basically guarantee you he would not rank elite at his level of practice.
Okay, so I stopped shortly after they talked about their justifications for using ballistic gel as a shock-absorber.
First, and most importantly, we are talking drastically different time periods. The breastplate being used for the demonstration displays curvature that is much at the heart of later plate-armour evolution, and specifically to deflect arrows. This level of technology would have been absolute state of the art in Warband's time, if present at all. I would contend that it would not be present, because armour like this came at a time when cannons were part of siege warfare, and in Warband I don't recall seeing any cannons, and instead catapults and trebuchet take their place. Bannerlord is supposed to take place roughly two centuries prior to Warband.
Between that and the use of ballistic gel for cushioning, this video really isn't very relevant. I went back and watched the slow-motion footage, and it's laughable how the breastplate is moving to disperse the energy. This is not even accurate to the time period.