When I worked in Sardinia in the 80s, the festivals on the island were far and away the best in Europe.
I’ve written more on l’ardia di San Costantino, the incredible horse race held in Sedilo, where I lived for four summers.
Around Easter, don’t miss Sartiglia in Oristano. Horses again, this time with riders who, in full costume, try to skewer a star hanging over a sandy track.
You can get a Sardinia Map and Guide on this site.
Sardinia is a fascinating place. Don’t get hung up on the Costa Smeralda. Go to the interior.