I feel Apple Watch is probably a strong contender. I asked grok the question, and the response was

“Apple Watch: Apple emphasizes transparency and user control, with data stored locally on the device or iPhone and encrypted during transmission. Their privacy policy limits data sharing with third parties, and users can manage data-sharing permissions easily through the Apple Health app. Apple doesn’t sell personal data, though it may use anonymized location data for geographically relevant ads. Note that deleting specific data categories is not possible—it’s an all-or-nothing approach.”

If you want the full answer, you can view it at https://grok.com/share/bGVnYWN5_60793e0b-e9e0-4c8a-b2b5-cc886dabb8ee