Check out Cue Tube, they have a bunch of scenes with sound effects/dialogue but no music. They are free to download and use.
My other recommendation is creating some of your own film. Especially something simple like nature shots are very achievable with either a camera and a few hours of learning Da Vinci Resolve, or using free stock video from a site like Pexels
I've enjoyed Andy Hill's book: https://www.amazon.co.uk/Scoring-Screen-Secret-Language-Music/dp/1495073734
Not sure exactly what the dramatic theory is, but its pretty comprehensive :)
Check out Cue Tube, they have a bunch of scenes with sound effects/dialogue but no music. They are free to download and use.
My other recommendation is creating some of your own film. Especially something simple like nature shots are very achievable with either a camera and a few hours of learning Da Vinci Resolve, or using free stock video from a site like Pexels
You will need to start JACK from qjackctl before any application will be able to use it.
You will also need to route audio from musescore to an output.
There are some great tutorials online about how to do this. Have a read through this: https://jackaudio.org/faq/jack_on_windows.html