Red Hat's Ansible Tower's documentation states that it can only be run on Red Hat Enterprise Linux. I can see once upon a time it could be run on other distros, such as Ubuntu. Is there a free Linux distro that Tower can still be installed upon?
The Ansible Tower Requirements still states
CentOS 7.7 or later 64-bit (x86)
you must have valid subscriptions attached before installing and running
An other option might be to use Ansible AWX
AWX provides a web-based user interface, REST API, and task engine built on top of Ansible. It is one of the upstream projects for Red Hat Ansible Automation Platform.