brz: ERROR: unknown command "dh-make"

Solution 1:

Ok, It seems dh-make command support was removed from bzr plugins (package brz-debian) since ver 2.8.51:

breezy-debian (2.8.51) unstable; urgency=medium

  * Drop the dh-make subcommand.

https://github.com/breezy-team/breezy-debian/blob/master/debian/changelog#L74

The solution is to downgrade brz-debian (2.8.51) to brz-debian (2.8.42) from Ubuntu 20.04:

wget http://mirrors.kernel.org/ubuntu/pool/universe/b/breezy-debian/brz-debian_2.8.42_all.deb
sudo dpkg -i brz-debian_2.8.42_all.deb