Thanks for that additional information. I understand the Mac is crashing, you determined the reason has something to do with a FitBit file, and although you were able to locate that file you're having trouble removing it.
I suspect one or more of the Kernel Extensions shown in that FAF report will turn out to be a factor. That could be bad news since the ones in that report might be on the order of eight or so years old, and it was during that time Apple "froze" (for lack of a better word) certain "legacy" Kernel Extensions before they locked it down for good. Nothing goes in... but the bad news is nothing comes out either, and without any help from the Goolag you're stuck.
Having said that I hope dislodging it will not prove to be an insurmountable task.
EtreCheck will gather copious information regarding that and other causal factors and generate a comprehensive report. The app does not affect a Mac in any way, and its report will be de-identified. Instructions for using it and posting its report in a reply are here: How to use the Add Text Feature When Posting Large Amounts of Text, i.e. an Etrecheck Report - Apple Community.
I and any helpful others will be able to examine that report and hopefully come up with some meaningful suggestions.
