As I recently enjoyed a bout of Covid on board QE, I assume the procedure is the same on all ships:
After my husband tested positive, I contacted the medical centre. As he had symptoms for 2 days before testing positive he was asked to remain in the cabin for a further 3 days - so 5 days from symptoms. While I tested negative I was free to roam the ship. And the same process applied to me once I tested positive. It’s basically an honour system and no further tests were administered by the medical staff.
Paxlovid anti viral medication plus consultation was US$ 900.
Daily restaurant menus were supplied and food delivered hot and on proper crockery / cutlery. Breakfast via door knob card.
Library books, fresh fruit, fresh linen, anything within reason was delivered. Laundry was free.
Once the medical team advised quarantine was over the room was fumigated and the steward allowed to enter.