Garmin swim2 do not upload healthy statistics to Garmin Connect, although it uploads activities correctly.
Have you tried to unpair and re-pair the device from phone / GC and redo.?
1. Remove watch from BT settings on phone
2. Delete GC app from phone
3. Soft reset watch (hold in light switch until watch shuts down completely, then after say 20s , restart it)
4. Restart phone
5. Reinstall GC app and sign in
6. Re-Pair watch to Phone / GC app.
