I changed mine a couple of years back when I customised my interior… take off the seal around the inside that hides the roof lining edges… if this has been messed with previously and not re fitted properly it can foul the blind slider rails!
Failing this….. it’s time to drop the roof lining and inspect further
The blind brackets are held in with a few torx screws
As everything with fiat …. It’s always a bit more involved than you would think!! Give yourself plenty of time