The FreePBX packages used on the current version of Casa (and on some of my Linux servers) are now on v17. This supports PHP 8.2 which ships in RHEL9 and its clones. They are available in the Lux repository for Almalinux 9. These packages are one of the central components that characterize Casa.
Please note the peculiar reasons why the FreePBX packages were created, which is to address the original FreePBX tendency to take over the Linux environment in a complete and exclusive way. With v17 it even would be required to build a new Debian server, entirely dedicated to the PBX function. The old hard manual installation procedure, which was not recommended but still mentioned, completely disappeared. This have some consequencies, which you may read about in the main package README.
And please note the license of the FPBX packages too, which at the moment allows an exclusive non-commercial use. You can easily obtain an exception even with absolutely no payment. These packages were not built to earn from them. The requirement is that they are used in a free manner in a free environment which is going to remain free.