Hey there!
Support for EL 7 was removed with Foreman 3.4. (one of the refs or another here)
So, as you can see here currently only EL 8 distros are supported/it’s only possible to install Foreman + Katello on. (For a Foreman only installation it’s also possible to install on Debian 11 and Ubuntu 20.04)
Making it work on EL 9 is under work right now and can be tracked here.