For Taoism, we can look at Xu Dishan's History of Taoism, which is the earliest history of Taoism in modern China, and then look at Li's Overview of Taoism and Japanese scholars' History of Taoism. These books are not thick, so you can have a basic understanding of Taoism after reading them. Buddhism can be found in the history of Buddhism in Du Jiwen.

Supplement: The immortal books that can be read are mainly the encyclopedia of Chinese immortal health preservation, as well as Hu's books, all of which are inherited. In addition, Hong Jianlin has a book "Decryption of Fairy Learning-Taoist Health Preservation Secret Library", which can also be read. Tian Chengyang has the practice of Taoism in China.