I use Cyclemeter on my iPhone 8. I use the Premium version, which is $10/year, which is great compared to the monthly charge that Strava has. However, Cyclemeter doesn't sync directly to a FitBit, so I have to sync Cyclymeter to Strava free and that (theoretically) syncs to the FitBit. However, as of late, Strava has stopped syncing to FitBit. I have tried everything I have found by searching to get it to sync, but nothing has worked.