Sorry for such a long post but you might find this enlightening.
I used a Versa 2 on my Moto G6 since 2019 and had no problems. Considered getting the Sense in October but waited. Costco had it on sale around the holidays so I popped for one. Other than the ECG and temperature functions, it installed fine and ran great for a couple weeks. After a recent update around 1/20, I noticed my sleep sessions weren't syncing. A quick check showed the last was two days prior, the day I got the latest update. Sync attempts resulted in the "Fix It" message which none of the suggested remedies worked. I remembered there was a Windows 10 version of the Fitbit app, fired that up and surprise! The sense was found but would not complete the install just like on the android app. Tried my old Versa 2 and the same result. After much tinkering (watch Factory resets for both watches, complete app re-installs) I got through a setup with the Sense but it was stuck on its initial "Download the app" screen. More tinkering and got a prompt to update the firmware. That hung midway through the update, luckily just the download portion. More tinkering and got the firmware update to complete only to have it notify there was another update. REALLY?? Two firmware updates in two days? That's fishy. More tinkering and the second one finally took but with the same result of the stuck boot screen. It still said it was syncing in the app though. At this point I have both a Versa 2 and Sense that don't work. I've tried alternate devices (Windows 10 and a Chromebook) with the same results. I did hear that Google finalized and aquired Fitbit and am now wondering if this mess has something to do with it. Luckily I purchased the Sense from Costco. I'll try their Concierge service as they have priority when calling any companies support service. Costco has gotten support on the phone in minutes where with some companies it could take well over an hour. If they can't fix it I'll be returning the Sense and can only imagine many other members might do the same.
