I offer two packages for configuring ntp service. One for IPA server and next for IPA client. Each package contains all supported ipa ntp modules for the server and client, respectively. These packages do not dependen on specific ntp services, so their installation will be successful. The only condition for installation is the presence of IPA server or IPA client in the system. If the system does not have any ntp services, the user can add the option "-N" and all settings associated with time synchronization will be ignored and the installation of freeipa will continue.
The user has to choose whether to install the package with the ipa ntp modules or not. As you see the setting is quite flexible.
As I already wrote, the user can refuse and completely ignore the ntp configuration using the "-N" option. The priority of choosing the ntp service is the following: chrony, ntpd, openntpd.
Added missing parts to my design page.