I have had many Fitbits over the last few years and have been thrilled with most of them. But the problems for the last 2 (Charge 2 and now my Versa) have made Apple products looks pretty darn good right now. I have been a loyal Fitbit user for the last 8 or 9 years, but my phone was stolen yesterday and I ended up with an Galaxy A20.....nice phone, but apparently Fitbit won't pair with it. Even laptop lasn't been able to sync with my Versa for months! I have no idea what you've done since the early days of the early clip on version, or the Charge, but it sucks! Really turned off right now. Thankfully I have an Ipad Pro that still syncs....REALLY makes me lean toward the Apple Watch/Fitness Tracker. This crap with Fitbit has been going on for too long. FIX IT or lose long time customers.
When you have multiple devices you can sync with, sometimes it helps to temporarily turn off bluetooth on ones you do not want to sync with.
I'm aware of that issue and I actually drove to our local cemetery and tried it there. I didn't think any of the 'residents' would have their bluetooth turned on. Still didn't pair.