Can traditional culture be described as in the ascendant?

Obviously not, it is to describe new things.

Party: Immediately; Xing: beginning, starting; Ai: Stop, it's over. In the ascendant means that things are developing without stopping. Describe the vigorous development of new things.

Traditional culture is not a new thing, and it cannot be said that it is in the ascendant, but this idiom can be used for some new phenomena involving traditional culture. For example, the study of China traditional culture by western scholars is in the ascendant.