If you want to exchange it for Thai baht, it's better to exchange it with a large face value
Of course, the smaller the denomination, the more practical it is. But banks generally have small denominations, which are not easy to exchange. It's more than 4000. It depends on how many days you plan to play.
Many places can swipe cards. UnionPay is OK, so you don't need to change too much cash. Of course, the smaller the denomination, the better the circulation. 500 yuan is already large.