Even before getting to the main point, bringing that money into USA as a traveler / visitor will be a hurdle as a threshold exceeding $10,000 must be declared upon entry. Will they allow the entire 5000 OMR stack in or would that be confiscated even when declared?
Like this: after paying for the food in $, suddenly giving them more money: I’m only a visitor (as I only have foreign currency, i.e. Omani Rial in cash) being like, “Here is 5000 OMR ($13,020) for your efforts” so despite that being a lot of money, will they take it?
It varies with the server and how much work was done. If you explain it to the person it might go better. At some places the server gives a cut to other staff that help with the table. At cafes with a tip jar it is divided up at the end of the shift. The only certain rule is don’t tip with those fake half bills with a religious flyer on the other side.