new MyPickup;
public OnGameModeInit()
{
   MyPickup = CreatePickup(lalalalalallala);
}
public OnGameModeExit()
{
   DestroyPickup(MyPickup);
}

public OnPlayerPickUpPickup(playerid,pickupid)
{
   if(pickupid == MyPickup)
   {
      ...what the pickup should do
      
      SetTimerEx("PickupRespawn", Time, false, "d"); //https://sampwiki.blast.hk/wiki/SetTimerEx
      DestroyPickup(MyPickup);
   }
}

forward PickupRespawn()
{
   MyPickup = CreatePickup(lalalalalallala);
   return 1;
}