I am not sure what exactly 'passporting rights' means
i understand it to mean that an EU bank that is licenced in any EU country, is given the benefits of being licenced in all other EU countries.
Since UK banks are no longer licenced in an EU country, they lose those benefits at the end of the transition period.
It's very much like the idea that if you are, say, a Chartered Engineer in one EU country, and recognised as a Eur. Ing., you can ply your trade in other EU countries without having to spend seven years gaining new qualifications in that country.
No doubt our government will sort this out in a few days. After all, it's the easiest deal in history, and we hold all the cards.
Nicht wahr?