I also think that to be taken from a Celebrity Suite to an OV is unacceptable.
I am really sorry you're sick and even sorrier this happened to you!
Someone earlier in the year reported that she had claustrophobia and refused the inside cabin and was moved to a balcony. It certainly sounds like, while you may not actually have claustrophobia, you are experiencing mental anguish and I don't think you should be as accepting as you have been to your accommodations.
We also will continue to cancel future cruises until we're sure that , if sick, we can either remain in our booked cabin or, at the least, be moved to something with a balcony.
I don't agree that everyone knows they'll be moved to deck three. Lots of reports of people being moved to balcony cabins. (And some even getting to stay in their own cabins)
It does however seem to vary by ship and even by sailing.
Someone posted a thread about a month ago trying to determine what would happen if they got Covid on their cruise and they got multiple different responses.
If Celebrity wants people to feel confident booking and sailing I think they need to put out a fleet wide statement of what will happen if one tests positive during a cruise. (And then stick to it!)