Update system except thunderbird, due to critical implementation of enigmail into TB
Instead of an command to update all packages but thunderbird, you set thunderbird to not update, then update the usual way.
You can say
sudo apt-mark hold thunderbird
That will prevent updates from being applied until you set it back to unhold
Update your system as usual.
Reference: https://manpages.ubuntu.com/manpages/bionic/man8/apt-mark.8.html