Commercial Modules are only supported on the official Sangoma Distro: Download | FreePBX - Let Freedom Ring
However, if you don’t need commercial modules and want to install OSS FreePBX, consider following one of the guides in the FreePBX Wiki. I personally have Debian 11 + FreePBX16.
With that being said, if you specifically want to use Rocky Linux, it seems like getting FreePBX to work on Rocky Linux is quite a challenge.
Disclaimer; Rocky Linux is planned as the the future official FreePBX Distro. However, it does not seem like the alpha version has been made public yet.