Shouldn’t the airline cover the tip? They’re the ones who lost your luggage, all costs of returning it to you should be on them. You pay an airline to check a bag. They’re supposed to deliver it to you at baggage claim after your flight in exchange for the money. They don’t have to refund you when they fail to do so.
When they finally find your bag, and set it up for delivery, and it shows up at your house or hotel you find this: a code to Venmo a tip?