i think it depends on whether you’ve changed the time on your device. if, say, your camera still reflects your home time zone, then i would upload those photos using your home time zone. but if, say, your phone automatically changed its time zone to your destination time zone, then i would change time zone in iNaturalist before loading those photos.
you can also look at this thread that i referenced earlier: https://forum.inaturalist.org/t/automatic-time-zones/7760. it contemplates a system change to address the need to change time zones in your profile settings, but no changes to the system have been made at this point.