Perhaps get rid of the stuff Bitdefender is inserting into Thunderbird and try without it. The first thing I see when I look at your crash is Thunderbird is unable to shut down because of an addon identified as bdThunderbird78@bitdefender.com As a quick test, hold the shift key when you start Thunderbird to force it into troubleshooting mode and continue when prompted. This should prevent Bitdefender inserting code into Thunderbird's process.
Bug 1665577 Comment 45 Edit History
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[Wrong bug posted in]