A/C issue

So I was driving once to Nashville, TN with A/C on. For the first twenty minutes it was working great blowing cold air on both driver's and passenger side. Then, passenger side stop blowing, then both sides kind of gave up blowing at low and then at high. Then we can hear A/C trying to blow via vent (cold air is present) but it is not really blowing out of the vent. I can feel the icy cold air but it just stops blowing like it should. So I thought maybe this is my first BMW and maybe I am just not familiar with its A/C. Now, I had to drive from TN to TX three days ago same thing happened so I had to completely turn it off for a while like an hour while the windows are open so I did not suffocate. Then it works again but it is on and off. And repeat so I can cool down for about next ten minutes or so then again the cycle repeats. I can hear the blowing noise even at 'Max A/C' but I do not get the kind of strength I can usually feel in my face with our family van. It is not a warm air it is icy cold but blower seems have issues? The dealer thinks it might be due to low Freon but I think this is blower issue that is other than the Freon? Thank you so much for your videos on YouTube and this opportunity to ask for your expertise!