One to consider may be Jonathan Spence’s Emperor of China: A Self-Portrait of K’ang-Hsi (1976). Spence is an excellent biographer, and the stylistic choice of only using quotations of the Kangxi Emperor, such as diaries, public statements and attributed quotes, makes for quite an unusual read. It is, admittedly, not exactly a day-to-day description of the sort you’ve asked for, but rather presented as a series of more philosophical musings on various topics, it’s still very much worth considering.