my favourite factoid as to why the ship was so unstable:

dutch shipwrights were generally considered the best in the world at the time, and many of them were hired to work on the vasa. they were involved in the drafting as well as the actual building. but because half the builders were swedish, the plans were made with no text on them, only units. so the decks would be marked as so-and-so feet tall, so-and-so feet wide, etc. also, to ease communication issues, the builders were split by language, with the swedes building the port side and the dutch the starboard.

now, there is no evidence this, it’s been extrapolated from relevant history and the state of the wreck, but the story goes that the reason the vasa is ever so slightly asymmetrical is because the swedish foot was slightly longer than the dutch.

Edit: also, little known fact: the vasa has a sister ship: Äpplet. she was finished a little later and led a far more successful life, in that she lasted through the thirty-year war, but she shared a fundamental problem with the vasa: nobody needed a ship that big. äpplet was deliberately sunk in one of the outlets in the stockholm archipelago in order to create an obstacle, and was only rediscovered five years ago.