Final Cut Pro X 10.4.8 keep crashing after clear all preference

Hi, my Final Cut Pro X keep crashing at one of my project. After I forced quit and restarted FCP, it still crashes once I place cursor on any files/functionality in FCP software. I tried holding Opt-Cmd when launching the application and opening a backup library. But it doesn't work this time, still keep crashing on backup project. Please help me with this issue. Thank you!