You can turn off the audio guide from the workout screen in Samsung Health.
Once you've started a standard workout from the Home tab, such as running, biking, or hiking, you'll need to tap More options (the three vertical dots) on the workout screen.
Then, tap the switch next to Audio guide to turn it off.
If that isn't helpful, this might help
https://www.samsung.com/us/support/answer/ANS10002419/