I’ve been exporting my data automatically from the garmin webservices with the intention to make a grafana dashboard myself. So this is interesting, but do you still need the garmin app to sync the data?
From what I’ve read, you can access the data on the smartwatch by plugging in a USB cable. The watch will connect over MTP, and the data will be in .FIT files. You can just copy-paste them with a file manager.