Previously had several Fitbits, didn’t like the build quality. Just seemed to have lots of issues with crashes, straps breaking, moisture getting into the watch even when being careful with it, etc.
Had a Fenix 5 for 4 years and love it. Very durable, all the data of the Fitbit plus more, and with a metal strap it looks more like a normal watch. On the occasions when I’ve needed to use it to record a ride or other activity it’s much more feature rich than the Fitbits I had - ability to pair devices with ANT+/BT like PM, HR strap, etc, and you get the full workout data in Garmin Connect for analysis. Could be the more recent Fitbits have improved on that front since the models I had though.