This looks nice, it also imports data from Garmin Connect? If I use Garmin Connect to sync to Strava, should I use the Garmin integration to have more data?

I'd like to have a way to archive and keep all my workout data locally and this looks interesting

You can only sync from Strava OR Garmin, not both at the same time. If you have a Strava subscription, I think setting up the Strava import will be best