A .gpx file that is intended to be a course file is not required to have any timestamp with the route points. There will be a timestamp in the metadata section but it's not required either (I think).
So this does beg the question how the OP is getting the .gpx file and what in fact the .gpx is built to be used as.
Garmin's sporting devices I'm use to typically give .fit files that have to be converted to a human readable format. So how one converts those files and to what they convert them to can make a difference.
Last edited by Iride01; 12-13-22 at 10:34 AM.