Again I wanted to reiterate my solutions:
For the free version I have this working reliably (if you're on windows you can skip the Virtual Machine part):
https://hellomihai.wordpress.com/2018/07/04/gopro-video-gps-telemetry-merging/
For a costlier solution, I use RaceRender.
I am able to use these 2 methods reliably to stitch long videos
