Unfortunately, Samsung Health doesn't currently offer a direct option to customize the timing of these notifications. The app is designed to send them at a fixed time, as part of its daily summary or reflection feature. We understand how useful it would be to have flexibility in setting a preferred time for these reminders.
Your feedback is extremely valuable, and we encourage you to share it through the Samsung Members app. This ensures that our development team is aware of your suggestion and can consider it for future updates.
