I have similar problem with syncing new activities. do not depend on distance.
this is happening.
1- turn on BT on smartphone
2- open SA and tap on watch icon
then the syncing started picture above
then it continue wit syncing POI, GPS performance,
then sa shows syncing activity data
and then, inmediatelly the syncing crash with this
tap on retry finish with same problem.
then I turn on and off BT on device. not help
restart smartphone and watch. not help
forget watch restart both devices, pair watch again. not help
forget, uninstall SA, restart both devices, pair them again. not help
but after many times tapping on retry, turning BT on/off, restarting devices the activity sync. I dont know which step help.
steps, calories, sleeping is synced
watch Spartan ultra - latest ver.
SA - 4.49.1 no beta
smatphone moto g9 power
android 11 - actualization from 1. november 2021