Ubuntu 20.04 Does have Perl installed.
At least if you look at the official Ubuntu docker images by Canonical.
tomodachi@delacroix ~ $ docker run -ti ubuntu:20.04 perl --version
Emulate Docker CLI using podman. Create /etc/containers/nodocker to quiet msg.
This is perl 5, version 30, subversion 0 (v5.30.0) built for x86_64-linux-gnu-thread-multi
(with 57 registered patches, see perl -V for more detail)
Copyright 1987-2019, Larry Wall
Perl may be copied only under the terms of either the Artistic License or the
GNU General Public License, which may be found in the Perl 5 source kit.
Complete documentation for Perl, including FAQ lists, should be found on
this system using "man perl" or "perldoc perl". If you have access to the
Internet, point your browser at http://www.perl.org/, the Perl Home Page.
But it's no longer seen as the best choice for a high level scripting due not being available on all platforms, not being that popular and not fully backwards compatible with older versions of Perl.
If you want a programming language more likely to be fully supported in the future and across distributions and operating systems look into Python or Ansible for your local shell-scripting and automation needs