Has anybody else had the same experience with the looseness of the dough after all stretching and folding? It does not feel firm at all!

Anna, I haven’t baked this recipe so keep that in mind. Most any hand mixed sourdough recipe will be more loose than a kneaded bread dough, if that is your context. Sometimes it almost oozes. Several things influence the structure of the dough, including temperature, humidity, flour type, and obviously the ratio of water to flour in your recipe. As long as your dough holds together and you can shape it into a loaf, you’re doing things just fine.