Export from Trasely
Choose Export → GPX. In the iOS share sheet, open the file with COROS or save it to Files first.
Best path
Open the GPX file with the COROS app, save it to your route library, then sync the route to your watch.
Format: GPXApp: COROSMenu: Navigation
COROSRoutes
Save Route
Watch Navigation◉
Save in COROS
When the GPX opens in COROS, tap Save or Save Route. The route appears in your route library.
Sync to watch
Open the route in COROS and choose Sync with your device. Keep Bluetooth on and the watch nearby.
Start navigation
On the watch, open Navigation → Routes, select the route, and start it. Some models require starting an activity first, then selecting Navigation.
Reference: COROS downloading and using routes.