I have a Huawei GT3 watch which I use to track my cycling activities. This goes into the Huawei Health app. I then use an app called Health Sync to transfer these activities into Strava. I do not track activities with the Strava app.
This works as expected, tracking duration, distance, speed, heart rate and route in Strava.
What fails is then syncing these activities to Google Fit using Stravas built in integration. For activities to show up in Fit I need to open each activity in Strava, use the "edit" feature and then save the activity again (don't even need to make any change).