I know of a modern cultivation novel. The main character is a middle-aged man, and it's called Return of the Emperor of Cultivation. The plot of the novel was that the protagonist, Chen Chen, obtained a dream scripture and fell asleep because of his cultivation. The dream lasted for 3,000 years, but only three years had passed after he woke up. After waking up, the entire world had changed. Chen Chen had also become different. In the city, he began to re-cultivate the path of a Martial Monarch Realm expert. I hope you like my recommendation. Muah ~