CA will work on pretty much all OS. Linux, Windows, MacOS. The documentation doesn’t cover each explicitly, but gives the list of requirements. Ubuntu is a Debian derivative, using Apt the packages and setting up really aren’t that different from Ubuntu.
If you let us know what is going wrong when you install and set up MySQL and php, we can direct from there.
Update: We use Ubuntu 22.04 or 24.04 for all our installs (stick to the LTS versions). We have also supported a client on RHEL 9.