Thanks for the additional information.
It appears the latest samba version did install correclty, yet nmb seems to still look for Samba 4.4.4. As I result, I would first restart your machine to reload everythin, as it always prove useful after so many updates.
I would then guide you towards the excellent troubleshooting that @Haioken did in the thread I linked above (and pasted below):
In particular, it started with:
systemctl status nmb.service
journalctl -u nmb.service
systemctl status smb.service
journalctl -u smb.service
Make sure to copy + paste the outputs for both of these (the system shell we use, Shellinabox, let’s you use Ctrl + C to copy) so that we can see all details.
These should help a little more, hopefully.