I use Teamviewer, but I do not use 2FA OTP. It seems people with 2FA turned on are the ones that have gotten hacked.
This makes me think the Teamviewer people saved a copy of customer 2FA QR codes and someone accessed it.
I know a few companies do this.
and that is the only way to hack it, inside employees are the one to trust less, same thing for microsoft win 10
while i may trust microsft as a company, there can be one or more bad guy working there that, based doing his work, he is working on stealing bitcoin wallet without being noticed