I was going to recommend VLC, but the android version does not have that feature.![]()
I did find this "top 10" review:
https://itechgyd.com/best-video-editing-apps-android/
Regarding the file naming based on the capture time not the video time, I have never seen it done any other way.
Found something useful, contains a guide too.
How to grab 8MP photos from 4K video on your Android phone