How to normalize a table with multiple cells that have multiple values?
Normalisation is to remove information from tables, that are repe4ated by many times and ids as int are smaller than any text.
The bridge Tables you need, because you have a m:n relationship between film and users(cast, director, musician...)
Occupation is in my opionion a attributs of the relationship between film and user
Film (idfilm,Titel, plot,Wiki_Page, year,... )

Film2user (idfilm,iduser,idtype)

type  (idtype,occupation)

user (iduser, Name, Birth,...)

genre (idgenre,name)

Film2genre(idfilm, idgenre)

as you develop further, you can add more attributes or tables if you find more such redundant information