Dear jfp2150,
I'm Dyari. Thanks for reaching out. I will be happy to assist you in this regard.
As you know, Windows 10 S mode allows you only install apps from the Microsoft Store, therefore, there are some of the best video editing apps:
1-Screen Recording:
Debut Free Recorder (Free)
Screen Recorder by Animotica
2-Video Editing:
Movie Maker - Video Editor
Video Editor Studio
Animotica - Movie Maker
3-Sound Editor
WavePad Audio Editor Free
Please let me know if you need further assistance.
Stay safe