I changed the sync frequency. I don't see an immediate change.
The sync scheduler is based on the destination warehouse timezone. The starting point is always at midnight plus an offset of +0 to +59 minutes. When you change the sync frequency, it will take effect immediately based on the midnight starting point.
If sync is set to run every 6 hours, changing the sync frequency from 6 to 8 hours will cause the next sync to run at 8 AM.