I think you needed a bigger weight than that bag of water. Bags like that are good for smaller jars. With bigger jars I have seen then use a glass cup that touches the lid to hold the cabbage under the salt water. That is such a big jar you would be best with a coffee mug.
You dry it without pickling mean fermentation. At the end cut in smaller pieces and dry it for three days. We traditionally dry without fermentation. It's very delicious. Jay bharat.