There was a fix for GoPro playback here: VideoPlayer: various fixes by FernetMenta · Pull Request #13095 · xbmc/xbmc · GitHub
This is master branch (i.e. Kodi 18/Leia only) - Not in Krypton.
You can try a testing build [TESTING] Kodi 18 (Leia) builds for Vero 2 & 4K