Why is the epoch of the 14-15 centuries called the revival of Russian culture? Is this legitimate?

This definition is connected with the fact that after the Mongol-Tatar invasion of 1237-1241, Russian culture fell into decay, stone construction stopped for almost 100 years, and literary tradition and crafts also fell into decay.

In the XIV-XV centuries, the revival was expressed in the following features:

Stone construction begins. For example, in Moscow by 1340 there were already three stone churches, and by 1368 a stone Kremlin was built. At the end of the 15th century, there was a real boom in stone construction; Italian architects worked in the city. Similarly in Tver, Novgorod and Pskov.
Literature. In the XIV century there was more chronicle information, in the XV century the Russian Chronograph appeared.
Development of icon painting. Dionysius, Andrei Rublev, Theophanes the Greek.