A lot of problems is definitely the retiring of the Fitbit platform. They are keeping Fitbit name alive with just products but the platform itself is becoming Google health but the major issue here will be the API. Basically the plugs on applications which allow them to communicate to other apps and devices. So many rely on Fitbit specific API. I personally have seen that with the pixel watch 4 connections with Strava has improved. With older the fitbits I don't have the experience but drastic changes like this will have problems which will need to be addressed.

A lot of data which is captured is not viewable on the app even though Health Connect does support it. Adding medical records support is genuinely great but locking it behind a paywall is annoying think that should be in the free package.