Anecdote (and obligatory YMMV): I purchased the Charge 4 when it first came out and after extensive usage, I tossed it in the trash. The final straw for me was when I was having a physical done and compared the HRM data of the watch to what the readings the nurse was getting with her device. The data reported by the Fitbit was wildly inaccurate compared to the readings that the nurse was seeing. I also compared my data to my wife's Apple Watch and noticed large disparities in GPS data when we would go on runs/walks together. In the end, I came to the conclusion that a) if basic heart rate/GPS data is inaccurate, what else is? and b) what's the point of collecting all this data anyway? At the end of the day, it wasn't providing me with anything that fundamentally improved my life and if anything led to more anxiety due to constantly tracking and obsessing over all of this data.

tl;dr - My Charge's data was questionable at times and completely inaccurate compared to a medical grade device. In the end, all the data tracking just gave me anxiety.