So, not to pile on more discouragement, but I've had the same problem. For me the problems started February 23rd, 2024. I bought my Charge 5 in June 2022 and it worked flawlessly until that date... more than 18 months. Since then, the device no longer provides resting heart rate... not once since it stopped. It still tracks HR in real time on the device, and reports that on both the browser dashboard and Apple app (iPad), but not on my Android phone app.
As for other biometric date, this device has rarely provided full sleep score, breathing rate, or heart rate variability data, but it has provided basic sleep stage data and SpO2. It still tracks and display my sleep pattern (but not sleep score) SpO2.
One other HR factor is worth noting. I have mild, intermittent afib, but that's been true since I bought this unit.
In some ways the most discouraging part of this problem has been the complete failure of Fitbit support to provide a diagnosis and solution. Even after a chat, phone call, and escalation, the feedback provided was the standard info offered to someone who hadn't been able to get this data from the beginning. It was all 'blame the customer' info explaining the several things I was likely doing wrong that kep the unit from working. It completely ignored the fact that the device had been working flawlessly re: RHR, O2, and basic sleep details for over 18 months! Whoever sent the 'solution' email to me obviously didn't read my problem description of look at the multiple screenshots I sent. Pathetic... and enough to make me consider switching to another maker. I've been a Fitbit customer almost since the beginning, but this experience tells me that might be a mistake.
