Hi. In Punta Cana it is customary to tip in restaurants and hotels, but the amount can vary depending on the quality of service and your level of satisfaction. It is generally recommended to leave a tip of 10-15% of the bill. However, some locals and tourists prefer to leave a tip in more generous amounts. I recently read an article on Cabarete Kiteboarding that details this
https://cabaretekiteboarding.com/tipping-in-punta-cana/ . There is a lot of useful information there that can help you better understand local norms and practices.