Hi,
I have two Nextbase 402G dashcams, which record GPS encoded MOV files, and use the Russian software Datakam Player (also known as Registrator Viewer) to export GPX files from the videos. The software provided by Nextbase crashed on my PC and I am not sure whether that has a GPX export option. The Datakam Download Website (in Russian) is here: https://datakam.ru/download/. The downloads are in the first section of links (“DATAKAM PLAYER для Windows/Mac”). As I have Windows 10 I downloaded version 6. They also do a Mac version.
The GPX files generated by this software contain coordinates at one second intervals and they seem quite accurate. Also they upload to OSM without any problem.
I am unsure how actively maintained the software is. It displays the GPS trace on various maps including OSM, Google and Yandex, but the licence keys for some of these have expired. Despite which, it still seems to work. It might be expedient to keep a copy of the zip install file, if the software is useful, in case you replace your computer.