Hi, Albertinho ....
1. On the video segment that John edited for me and included in his
Camino Frances series, I had my GoPro running the full 9 hours + of walking from St John Pied de Port to Roncesvalles. My impression is that John does the same thing with his recordings; except where things like weather prevent having the GoPro exposed. So it is pretty much a step-by-step recording of an entire stage.
The only time I paused was to change out a full 256 GB SD card with a fresh one. There were a few times where the iPhone GoPro App shut the camera down due to a weird Bluetooth foul up, but I would catch it and turn the camera back on. After the third time, I turned off the app and just used the controls on the GoPro.
2. I used an
Anker 20000 mAh power bank to power the GoPro for the entire 9+ hours. I did not use the GoPro batteries which only last me 45 minutes recording at a 4K 60p resolution. The power bank plugs into the GoPro via a cable. At the end of the day, there was still about 30% of the power left in the power bank. A power bank in the 12000 to 14000 mAh range would have been sufficient, and a bit lighter, too.
3. I do not use a harness,
I use a a clip attachment to the backpack's shoulder harness.
These can work well, too.
I then used a quick disconnect system so that I could quickly mount or remove the GoPro from the Strap mount.
I like this one a whole lot better than what is supplied by GoPro
Maybe this will be of help to you