iPhone XS AppleCare eligibility
So I'm planning to get an unlocked XS and I wanted to know if I can still get AppleCare on a used or refurbished one and also is Apple still able to repair it if its gets damaged?
No. A used iPhone XS would have no eligibility for AppleCare plans at all. A used XS is at this time still repairable however. XS was released 4 years ago, in 2018. Apple typically offers support for a device for a full five years, sometimes 6. So, it won't have service eligibility for too many years.