Can't update iMovie - not accepting Apple ID
I recently updated to macOS Big Sur and now I need to update iMovie. I went to update, however when I enter my login details using my Apple ID it says that I haven't used the iTunes store before.
I found a tip online that said I should update my billing details. I did this, but it still won't allow me to login and update iMovie.
Can you please assist? I see in other threads that it's recommended to delete the app and reinstall, but if I do this I will lose one of the projects I have in there that I wanted to edit. Thanks
MacBook Air 13″, macOS 11.5