Hello @Definit
This help page has the recommended steps for finding a lost Fitbit (<-- click link). Basically, you have to see if you can get the Charge 6 to sync with your Fitbit app to narrow the search area. Then, use an app to help pinpoint the location.
Please be aware that you need to do all this while your device still has battery life.
Rieko | N California USA MBG PE