SOLVED
I found a reference to the Android app "X-plore" which has the capability to copy files from Onedrive to OpenCPN directories.
It seems like a very capable app, but it took a while before I figured out how to copy/paste, It was explained here: https://youtu.be/5iz0Bz1A_98
/Jakob
Huge thanks for finding this X-plore app. Not only is it super useful for moving GPX files to/from Android, but it will also make managing charts far easier!
It's very, very helpful of you to come back to the forum and updating your solution. Thank you.