Find routes 
Gruzo Selection
Gravel Kalken - Berlare - Kalken - Destelbergen
82
72
35
Gruzo Selection Strava
- Open the activity on strava.com. The app can't export.
- Click ··· (the three dots) → Export GPX.
Garmin Connect
- Open the activity on connect.garmin.com.
- Click the gear icon → Export File, and drop the ZIP as it is.
That link shows gravel rides; switch the filter if you saved it as a regular ride.
Wahoo, Komoot and most bike computers export from the phone app — or copy the .fit file straight off the device.