Tianqi started to search for Yuemi after Bai Jue was reborn/resurrected. The accident that led to his "death" happened during the time Feng Yin waiting for Yuanqi's resurrection. According to the novel, Fan Yue met Feng Yin while she was still mourning and waiting for Yuanqi. Thus I guess the whole content of this story falls in the period when Yuanqi went offline (Feng Yin had to wait for 1000 years).
The timeline is: The original God realm, then Shanggu's martyrdom then 60000 year to Houchi & Qing Mu's story then 100 years Houchi's excile then 100 years for Shanggu to wake up then Bai (Black) Jue 's martyrdom shortly after that + 3 years Shanggu mourning before her kneeling for 500 years until Bai Jue's rebirth.
Yuanqi faced the destruction of his sect when Bai Jue returned (Shanggu kneeled for 500 year in the drama and 100 year in the novel). Shortly after that A Yin was killed by Yuanqi. It took 1000 years for her in the reincarnation cycles to return as Feng Yin. A few months later Yuanqi's soul dispersed to seal Nether world (Jiu Yu).
Therefore, Tianqi's accident happened about more than 1000 years after Bai Jue's rebirth. He saved Bai Shuo sisters shortly before the accident since mortal life was short. Fan Yue met Bai Shuo a decade after she was saved by Tianqi
