You need to tick the box in /settings:

Then it should update the Garmin activity name to match. Strava does send a webhook when you edit the name so edits should also come through.
Note that this works for new activities.
You need to tick the box in /settings:

Then it should update the Garmin activity name to match. Strava does send a webhook when you edit the name so edits should also come through.
Note that this works for new activities.