Not a YouTube channel unfortunately but there are several videos and documentaries about it.

The castle of Guedelon is exactly what you are describing.

In France a group of archeologists decided to build a full castle, from scratch pretending to be in the XIIth century.

A blacksmith is making the tools, they are chopping trees in the first forest around, extracting stones from a local carry, carrying on carts built by the Carpenter, making their own clothes …

It’s amazing !